Strangest Car Inventions: Ford Invents A Bizarre Way to Meet 1970s Emissions Standards

Learn more about this strange strategy employed on 1975 Ford Thunderbirds and Mark IVs to control emissions.

[@Somebody_in_TX_1960]

I had a 1975 LTD 4 door with 400M that had only 1 converter. I will never forget the response from a seasoned mechanic when asked. He said “if Ford could get it to pass emissions by putting a ball point pen in the exhaust, they would”.

[@toronado455]

😂

[@BlackPill-pu4vi]

My Mom RIP had a 75 Lincoln Town Car with the 460 and I do remember seeing that single converter on the driver side. I asked a Ford dealer mechanic and he said the slight backpressure from the converter pushed some of the exhaust go through the heat riser under the intake manifold and kept it hot without needing a special heat riser valve. And yes, the 460 did manage to meet emissions requirements for that year so, it saved money for Ford in two ways.

[@nathanhansford76]

That’s because ford knew how detrimental catalytic converters were to engines, in the early days they probably thought it was a government fad…

[@DrOlds7298]

Same car my family had from 1975-85. But we had to have ours removed to take it with us to Germany in '77. (Military Family) Wasn't any Unleaded Gas in Europe at the time. Plus a friend of the family was a long time Ford Dealer Tech and before it 'Went across the Water' showed my father a few things to remove,(One of those 'I can't legally do it,but I 'can' tell 'you' what to do??' deals.)plus we got a '74 Fuel Filler. I will say that years later when I worked for a used car lot,'our' 400 '75 Ford ran a bit better than most of the 'other' mid-late '70s 400 Fords I drove at work!!!

[@ronaldkovacs7080]

Ford actually had a restriction disc at the flange of some of their exhaust manifolds for this purpose and to operate back pressure sensitive EGR controls.

[@hobbified]

Cop tires, cop suspension, cop shocks, and it's a model made before catalytic converters so it runs good on regular gas.

[@xaenon]

I knew there was going to be a Jake 'n Elwood reference in here somewhere!

[@ZGryphon]

Fix the cigarette lighter.

[@xaenon]

@@ZGryphon Use of unnecessary violence in the apprehension of the Blues Brothers... has been approved.

[@TroyOnymous]

Grounding straps on the exhaust pipes back then was likely to aleviate radio noise, when you have high speed air carrying particulates through the pipes you get a buildup of static electricity, so you just bond them to the frame to dissapate them.

[@thewiseguy3529]

This explains why the exhaust smelled different amongst the different manufacturers. I always wondered why they all smelled different but burned the same fuel. Thanks Adam!

[@albinklein7680]

I live in Germany and we adopted catalytic converters in the mid 1980s. Some cars had electronic fuel injection with oxygen sensors and three-way cats. Some cars had weird and hyper complicated carburettors with vacuum controlled choke plates ("Vordrosselsteller") and gigantic cats. Those were a real nightmare to get running halfway decent. I was an apprentice at that time and we called those carburettor systems "Pierburg's revenge" (Pierburg was the biggest manufacturer of carburettors in Germany at that time). And some cars had normal and simple carbs and just a cat without any lambda regulation. And other cars had nothing and still ran on leaded gas (cats became mandatory in 1992 iirc.). We had also many different tailpipe smells then...

[@MacPoop]

Really?? I had no idea Germany had issues with the old school smog carbs (I thought that was just us!) and yes, they were a total bitch and a half to tune and get working half-good

[@SquirminHermanthe1eyedGerman]

@@albinklein7680 I was born in Augsburg 1967 but have lived in the States {Georgia} since 1975!

[@markhenkel2484]

@@albinklein7680 I bought an "American spec" Nissan Pulsar NX in 1985 while I was stationed in Germany. Drove it from the port. They gave you the catalectic converter in a box in the trunk and a plastic adapter for the fuel nozzle. That was before Germany banned leaded fuels.

[@albinklein7680]

@@MacPoop generally speaking they kind of worked. At least for a few tens of thousands of miles/kilometers. But after some time they became a real nightmare. The dreaded Pierburg 2EE carb for example which was used on cars like the 75hp MK2 Golf, the Mercedes 190 and the 2.0 Vauxhall/Opels. The idle regulation is a combination of solenoid valves, vacuum diaphragms and linear resistors, for example. If that stuff starts acting up, you are in a world of pain. And don't get me started with the hilarious EVAP system with mechanical valves and temperature switches which switch vacuum instead of electric current. Hilarious stuff. I had a really, really hard time with that sh*t when I was an apprentice in the late 1980s. I make good money today with that stuff, because I am one of the very few remaining guys who know how this mess works, though... Sorry for the long text!

[@fourdoorglory5945]

Very interesting video. Two things I remember most about 70s-80s catalytic converters: sulphur rotten egg smells and rusted heat shields that would rattle after just a couple Michigan winters.

[@bobroberts2371]

The sulfur smell was due to high sulfur content of the fuel not something the cat caused.

[@fourdoorglory5945]

@@bobroberts2371 Source please.

[@bobroberts2371]

@@fourdoorglory5945 My 45+ years in and around the auto repair industry. Cats don't " make " sulfur therefor it comes from the fuel EPA has info on sulfur in fuel.

[@SquirminHermanthe1eyedGerman]

@@bobroberts2371 you are correct, sulfur is naturally occurring in crude oil that has to be removed & if you smell sulfur the convertor is not doing its job

[@greggc8088]

@@bobroberts2371 Yeah it was. It meant it was working. The fix for complaining customers was to run a tank of leaded gas in it so the catalytic converter's effieciency would drop a bit and have less odor. That's the way we did it in the late 80's at the GM dealer anyway.

[@snerdsters8]

These are the cars of my youth. At the time, I was much more interested in sports/muscle cars. But now as an older person, I really miss the days of the big boats. Your channel really is fun for me to watch and be reminded of a great time in my life.

[@pcno2832]

The worst thing about GM's "pancake" converter strategy was the way they raised the passenger's-side floor to make room for the converter and to keep the considerable heat from the converter, in the days of carburetors, away from the carpeting. It made the passenger's seat so cramped that even with the seat all the way back, 6-footers had no thigh support and had their knees in the air. Ford's arrangement did narrow the passenger's footwell, but left it deep enough to stretch out a little. I'd say Ford had the better idea.

[@MarkWG]

Ford always had "The Better Idea"!

[@bernieschiff5919]

Burn through in the carpet was possible, using leaded fuel would damage the converter, and burn a hole in the carpeting, using a "test pipe" improved gas milage on the Chevy caprice I had. I agree, the exhaust systems overall were pretty bad, the long non-stainless-steel pipe would completely rust out every few years.

[@MickeyMousePark]

and parking in a field of tall grass could set the whole field on fire..

[@DrOlds7298]

@@MickeyMousePark Saw that back in '84. Took out about 5 cars in a grass field being used as a parking lot!

[@DrOlds7298]

@@bernieschiff5919 One of my older sisters had that happen to her car. Ran over something (we think) and the converter heat set her carpet afire. Luckily she had just pulled into her yard & was in reach of her garden hose.

[@johnpotter8039]

My first company truck was a 1975, pre-converter, Ford F-100 with dual tanks and an automatic transmission. It got, count-em, 8 MPG. With the AC on, it went down to 7 MPG. It dieseled every time I shut it off, in Park. I could reach 50 MPH climbing a gentle grade. I had to fill up (company credit card) almost every day. I took it to the company garage and the head mechanic "de-smogged" it. Mileage went up to 15-16 MPG, it stopped dieseling and could maintain normal highway speeds. Some "emissions controls", eh?

[@zzoinks]

I think this same channel has a video on another emissions control system where you have to adjust a valve somewhere to change how the car idled and ran. I forget which brand it was, maybe a Chrysler? And if the control was set incorrectly it would run poorly. But that also sounds similar to the carburetor adjustment for different altitudes, if somebody wanted to do mountain driving the adjustment is needed, and similarly back at sea level, else the engine doesn't run correctly, but that doesn't have to do with emissions controls.

[@viktorakhmedov3442]

Yeah I worked for PennDOT back then and one time we had a new emissions Ford diesel itself down the side of a mountain.

[@Paramount531]

CA used to require hang on devices for 66-70 cars, either a distributor vacuum retard setup, or in the case of my 68 VW, a hang on EGR system. There were no yearly tests, only when you bought the car did you have to get testing done. After that, the hang on crap went in the trunk until it was time to sell the car. As an added bonus on the VW, the hose from the crossover on the intake manifold to the spacer plate below the carb was made out of metal, like a flexible natural gas line. That chafed through against the engine hatch, resulting in a vacuum leak and a burned valve that was ignored by the previous owner until the valve dropped. I bought the car after that was repaired.

[@dougbelanger3479]

I remember working at a Sunoco station at 9 Mile and Schoenherr in 1975, we had a new Grand Marquis in for an oil change. 460, dual exhaust, one converter.

[@upsidedowndog1256]

GM's pancake was great. All of my friends took the caps off and drained all of the pellets. They epoxied the cap back in place with varying degrees of success.

[@Ozark_Bule]

I remember several friends doing that as well. They also cut out the gas nozzle blocker so they could use cheaper leaded gas which had the larger filler nozzle at the pump.

[@greggc8088]

There was a tool for that cap. We actually had to replace the pellets on some at the dealer. Blew them in with a special tool through the port.

[@SirOsisofLiver]

Dad had a '76 Lemans Safari with the 400. One of the first things he did was remove the cap and take the car for a rip to blow the pellets out. He did get the cap back in place afterwards. Not sure if it made much difference. Those were pretty tough years for cars.

[@TStheDeplorable]

I kind of think that was GM's intent!

[@kennydemartini2169]

I emptied out many converters back in the '80s. I chiseled out the plug, took the car for a spin around the block and hammered a freeze plug in its place afterwards.

[@steventoby3768]

I had no idea this was happening even though I was an adult in 1975. No question, if the car with a particular engine could pass emissions with only one cat, that's how it would be certified, no one would care it was asymmetrical. I notice there's a crossover pipe connecting the two sides, downstream of the catalytic converter. If the cat has more back pressure than the non-cat side, and also heats up the gases more, the two sides are different both in temperature and pressure. This would cause flow through that crossover pipe from the non-cat side to the cat side, mixing the untreated exhaust with the hotter gas from the cat and perhaps causing chemical reactions that partly de-smogged the gases from the other side. I theorize that's what made this system work. I think Ford's engineers deserve a lot of credit for their innovative solution to this emissions problem. I would be surprised if there was a technical article about it in the Society of Automotive Engineers Journal, but there certainly ought to be.

[@apsdev]

What if the left exhaust without cat has a valve in it that opens at a certain pressure. so all exhaust goes through the one cat with the crossover .. except when you go fast. But if you measure exhaust while its idle all goes through the cat. Maybe the engine is cleaner when you go fast anyway. i guess it wont have such a valve but it reminds me of what happens now that car manufacturers get sued, because the cars are sort of smart with computers and are clean when they realize that they are being measured. As i guess especially diesel cars are by nature dirty and its very expensive to make them clean . so when exhaust rules get more and more strict they start to use more tech but also more tricks. Like i guess run engines very lean when measured. The crossover seems weird .. as because a cat adds resistance ... part of the gas that it supposed to go through the cat goes through the crossover, so more gas would exit the non-cat exhaust than the cat-exhaust.

[@Gary7even]

I remember when the 76 Chrysler Cordoba came out and the ads touting the 400 Lean Burn engine with no cats, thus you could use regular leaded gas. That only lasted for one model year, as in 77 the 400 had cats.

[@davidam9454]

Because the lean burn engine was endless problems. My brother had one he cussed and finally killed trying to get rid of the lean burn mess

[@SUPRAMIKE18]

My grandad had one of those lean burn 400s that kept slowly ruining pistons at only 80,000 miles all 8 pistons were replacements and he sold it.

[@ThePaulv12]

The system was unreliable but the principal of operation was pretty good. Combustion temperature rises the closer to 14.7:1 you get but then as you pass it the temperature drops again So ELB worked by going so lean that the engine was running on about 17:1 AF and was lean cool because the mixture had so little fuel in it. It was detonation resistant because detonation only occurs in a certain band. A great idea but yeah, nah. Fuel injection solved all that. Interestingly, Jaguar V12HE engines took the operation principal of ELB and refined it to a high degree. The designed was baked into the engine from the pistons to the combustion chamber, the injection system and the ignition system. They still had cats though. It made the V12 engine last 15 or 16 years longer in production than it would have.

[@adamtrombino106]

My dad had a 76 400 4bbl with the ELB. Each time we went to an emission test, they tried to deny him for no cats. Each time he had to raise the hood and show the the tag NON-CATALYST. If you ordered the L code 360 4bbl 75-79, or P code 400, you got true dual exhaust with dual cats. The floor pans on those cars were mildly revised, and you also got a smaller gas tank to accommodate the pipes.

[@DrOlds7298]

@@davidam9454 I once had a Plymouth Gran Fury with that on it. I simply 'backdated' it & eliminated the Lean Burn. Chrysler even sold a kit to do this,this ought to tell you something right there??? Ran much better after that,and my MPG's went up!!!

[@michaelbuzzee1964]

That single ford Cat was massive!

[@DonTrishLayne]

Not positive but I think that is about a 73 Continental, only because I had one with a massive 460 in it if I remember correctly, great land yacht

[@45johngalt]

should have seen the stock cat on my 1990 bmw 525i, it was a "non restrictive" design and took up like half of the entire exhaust piping system.

[@bobroberts2371]

Ground straps This was usually to mitigate electrical noise that causes radio interference. Some modern cars do this as well, the PT cruiser has ground wires from the front struts to the inner fender.

[@JayMalone26]

My SL500 has a copper spring behind the dust cap on the front hub bearings to mitigate radio interference. That's back when Mercedes was ran by engineers and not shareholders

[@ML-jk3sz]

@@JayMalone26 Every company is run by shareholders.

[@MoparTech]

That ground on the PT(and Neon) is to keep the front wheel bearings from failing prematurely. When I was a young tech at the Chrysler Dealer and these PT's were new the senior tech that mentored me explained the previous generation Chrysler vehicles w/the same press in style wheel bearings would burn through front wheel bearings until they added the ground strap to help discharge the static electricity that was generated when the wheel spun.

[@Circlotron]

@@JayMalone26 Static electricity discharging through bearing surfaces can over a period of time cause those smooth surfaces to deteriorate. The copper spring might be to overcome that. It is a definite issue with large industrial electric motors that are operated from variable speed AC drives.

[@andrewdynes5300]

@JayMalone26 I had to Google the copper spring out of curiosity. According to "Mercedessource", it is to provide a ground path for the brake pad sensors.

[@JeffFrmJoisey]

I’d visit a friend who worked in a self repair garage mid 70’s. Lots of GM car owners would put their car on a lift, remove the pancake’s plug, then shove an air hose in the tailpipe and blow the catalyst pellets out into a bucket, then put the cap back. They said it gave them more power.

[@ronbrock6153]

I remember working in an autoparts store in the mid 80's. They sold cat "test" pipes, to see if your cat was defective and needed replaced. Funny that noone who purchased one ended up ordering a new cat.

[@roberteast4160]

Yeah most people just removed the cat and left the test pipe in.

[@k4106dt]

Unless you lived in CA and had to pass a smog test to register your car.

[@ronbrock6153]

@@k4106dt Thank god no, I have never lived in CA.

[@DaveMcLain]

@@ronbrock6153 Test Tube, "to verify the need" in very small type, "to replace catalytic converter" in a large font. Sal Tovella had them as a sponsor on his USAC stock car in about 1980.

[@xaenon]

Same. Then they cracked down on that and those 'test kits' vanished overnight. The company that made those things knew exactly what they were doing. Though they were not the only company to gimmick the emissions control regs. Did you know that Ford itself played games like this? Remember the days when Ford's half-ton pickup was called an F100? And then an F150 appeared and the two models were sold side by side and and both were half-ton? There was no major mechanical difference between them other than ONE: The F100 was declared at a slightly lower GVWR, which made it exempt from the requirements for cats. To avoid too much suspicion, and sell the more-expensive (because of the cats) F150, the F150 was offered with optional 360 and 390 engines (351M starting 1977), and the F100 only got a six-cylinder or 302. When the EPA closed the loophole, the F100 disappeared. Oh, there was one other minor difference: F100 2WD models usually used a light-duty axle, while the F150 got the regular 9-inch. Dodge and GM did similar things. Chevy's 'heavy half' is an example.

[@Prototheria]

That single cat always perplexed me until Saab came along with their turbo V6 with a tiny turbo on one bank.

[@jimmyaber5920]

A GM v6

[@greenbassboosts8872]

Asymmetric turbo is pretty cool. The way the turbo exhaust housing is part of the manifold is also kind of neat

[@gabrielv.4358]

what

[@travelcampingblacksmithing786]

@@gabrielv.4358the saab 9-5 had a v6 option. It had asymmetrical turbo charging. Pretty neat setup.

[@Zt3v3]

I took the clean air car course in 1996 to become a smog tech, the year OBD2 was mandated - Mixture control solenoids and back pressure transducers were the tech of the time, at least for most the cars on the road. Early emissions equipment was so bad too, but from 1996 onward, things got pretty good.

[@mopar3502001]

I remember those days. Back then, Mikuni Solex has designed the absolute worst carb to rebuild. A nightmare.

[@albinklein7680]

I live in Germany and I was perplexed when I saw the underside of an 1970s Oldsmobile with those weird crooked crossover pipes for the first time. Funny stuff.

[@mindeloman]

70s and 80s were a wierd time for American car design and engineering. The EPA was constantly coming at them to burn cleaner and get more miles per gallon and the NTSB coming at them to make cars safer. They were chasing their tails for a while. They never really recovered as they gave a foothold to the Japanese makes. Today, the big 3 make very few actual cars today. It's 90% trucks and SUVs.

[@albinklein7680]

@@mindeloman the German cars made for the US market were super weird, too. Especially Mercedes. The 350SE with the M110 V8 for example had 3.5 liters of displacement and 9.5:1 compression producing about 230hp in Germany. The M110 for the US spec model was enlarged to about 4.5 liters but the compression ratio was reduced to iirc. 7:1 and they had a super weird cam timing/profile. They were extreme gas guzzlers and ran like crap. Poor Americans....

[@ToolofSociety]

@@mindeloman Trucks and SUVs gave the biggest profit margins.

[@mindeloman]

@@ToolofSociety sort of why we no longer have affordable houses. Builders figured out the bigger the house, the more margin they make.

[@albinklein7680]

@@RobertJarecki gas prices in Germany were at about 1.20 Deutsche Mark in the late 1970s. And Diesel fuel was about 85 Pfennig. A typical Mercedes Taxi (240D or 300D) used about 8 to 10 liters of Diesel for 100km. An Oldsmobile Cutlass consumes at least 30 liters of gas for 100km in city traffic. It makes absolutely no sense at all to use such a car in Europe as a taxi. The lower price doesn't matter at all. It is all about cost of running.

[@billbraun6846]

The shop I worked at in the 80's had three customers with 1975 Mark IV's. All of them had the front seat belts cut and removed. I guess to make it easier to get into the rear seats. When seat belt laws came in the owners wanted these repaired. New ones where obsolete and every used Mark IV in my area had their seat belts cut too. We ended up putting in aftermarket lap belts.

[@RDEnduro]

My science teacher in highschool had one and i remember his giving a ten minute speech about, its his right to not wear one and his business etc. Haha he was pissed when they made the law

[@MUUKOW3]

​@@RDEnduroA teacher against the nanny state , that's a rare thing these days !

[@zzoinks]

​Sometimes people are dumb too, the people who don't wear seat belts are an example ​@@MUUKOW3

[@Vincent_Sullivan]

@@RDEnduro This surprises me. You would think a Science teacher would know some Physics! It should be easy for him to work out what would happen to him in a collision if he was not belted in.

[@LifeisGood762]

This is good information. If I ever buy a Mark IV I'll know why the seatbelts don't seem right, because they're not, they're aftermarket.

[@billymule961]

I remember in the 70's when riding behind certain cars on my motorcycle, it felt like hot particles of sand hitting me in the face. It was coming from the exhaust. I would either have to back way off, which usually resulted in someone cutting me off, or try and change lanes.

[@MrPinto1970]

epic you were getting blasted with molting metal

[@davidgagnon2849]

Interesting!

[@theda850two]

Love those '72 T-Birds ❤

[@curtislowe4577]

As late as 1977 VW's Rabbit (and probably the Scirocco as well) with a Bosch Jetronic fuel injection instead of a carb could meet EPA requirements without a catalytic converter. They bragged about it quite loudly.

[@PRH123]

I had a 76 fuel injected (mechanical) German built rabbit with the round headlights, and yes I believe it didn’t have a catalytic converter.

[@philojudaeusofalexandria9556]

Considering german cars' history of cheating on emissions testing... It's probably 50/50 whether it ACTUALLY met standards.

[@DarkAttack14]

@@philojudaeusofalexandria9556 No, it is not. This is before electronic controls that enabled VW to fake out the EPA during their dyno testing. They would run the vehicle on a dyno and analyze the exhaust output and at this time there was no way to fake out their analyzers by having the ecu adjust the engine maps

[@curtislowe4577]

@@philojudaeusofalexandria9556 I absolutely would not argue with that! Although the Bosch FI systems of the time were completely mechanical so the ability to have two completely different engine maps didn't exist. In the early 80s I bought a Pennsylvania built Rabbit diesel - still with an entirely mechanical FI system - in part because it had an EPA highway mileage rating of about 45 mpg. I had a 102 mile daily round trip that was all on rural blacktops with only 3 stop signs that didn't require full stops. The best it ever got when new was 42 mpg and as it broke in it stabilized at 35 mpg which was barely better than the 32 mpg the gas Rabbit highway mileage. That was my last German vehicle and my only diesel.

[@MUUKOW3]

​@@curtislowe4577I had a rabbit diesel ,a 79 and it averaged around 52 mpg ,that was a great commuter car

[@k4106dt]

I remember reading in 1975 about the new catalytic converters most of the '75 cars would use. Along with the pellet type was the honeycomb type, which is the type that the entire industry eventually adopted.

[@garbo8962]

One of the best thing auto makers greatly improved on was replacing carburetors with fuel injection. Had a 1962 & 64 Chevys that had to have spark plugs replaced maybe every 30,000 miles due to fowling &/oil build up.

[@1957GoldenRocket]

How did birds get into the intake ? 😉

[@greggc8088]

@@1957GoldenRocket 🤣

[@joedepoto]

Another bit of trivia is that 1975-1976 Plymouth Dusters and Dodge Dart Sports equipped with a factory E58 360 four barrel not only had an air pump instead of a catalytic converter. But those high performance Chrysler A-Bodies also left the assembly line with true dual exhaust.🤔🤷‍♂️🤨👨‍🔧

[@JBM802]

Yeah, they diluted the exhaust.

[@leewaken5059]

My "75" Corvette was anemic!🤦🏻‍♂

[@bradpnw1897]

More like choked almost to death

[@HarmonRAB-hp4nk]

hmm sorry one challenge us in our kit car coming off a highway off ramp it was a gt40 kit on a porsche frame... we went around at highway speed... he slide of and hit the fence. didnt have the heart to tell him it was a volkwagon 1865 cc in it LOL he truly believed it was a gt40 LOL we got a 6 cyl in it later and nothing could tough it. oh it only weghed 1200 pounds lol :-).. 18" tires.. I dont think you could peel that thing off the pavement it had so much traction it was llike driving a rc car.

[@Bagel-the-Beagle-1]

My 2000 explorer is too! Leaks everything but trans fluid!

[@buzzwaldron6195]

From internal engine changes... correctable with about $200 in parts...

[@markdrake2715]

My Dad had a 75 Camaro. It sounded good, but very anemic, too. 165 hp, I believe...

[@paulplack490]

Ford V8s had a history of odd applications which used the two cylinder banks separately. Ingersoll Rand used to sell a big air compressor that used one bank of a Ford V8 as a 4-cylinder engine, and the other bank as the compressor. I wonder if Ford put different size jets in one side of the 4-bbl carbs on these "half-cat" engines to get the fuel-air ratios to match.

[@paulwindisch1423]

There used to be a kit available to turn an air cooled VW flat four engine into an air compressor. The kit would come with a new intake manifold that only went to two opposing cylinders. This kept fuel out of the cylinders used for compressing air. The kit also came with air filters for the compressor cylinders, and a different cam that never opened the exhaust valves on the compressor cylinders and opened the intake valves every crank revolution so as to double the compressor output vs a regular four stroke cam. I believe it was called “Volksair”.

[@gabrielv.4358]

That is awesome

[@rhyoliteaquacade]

I lived near Universal Oil Products in the 70's. A couple of friend's got jobs driving the Catalytic Converter test cars all over the place, including the highways. The rear seat was removed and replaced with chart recorders to measure temperature and other parameters. They told me that one day they drove a car on the Illinois toll-road at high speed, turned the ignition off, pumped the gas and switched the ignition back on. There was a terrible backfire noise followed by flames and catalyst stuff going out the tailpipe. These were carburetor engines so you could do that sort of damage.

[@kkuenzel56]

That really takes me back. I started my 30 year career in 1977 as a Lincoln Mercury technician. I remember working on those early 70s Land Yachts!

[@edwardpate6128]

I bought a 77 Trans Am I bought brand new and when I pulled that converter and single exhaust with the crossflow muffler off and put duals with Corvair turbo mufflers it turned it into a different car!

[@PRH123]

What did ya’ do when they started doing annual emissions tests?

[@SquirminHermanthe1eyedGerman]

I did the same to my Trans Am & Z28s, really wakes them up

[@SquirminHermanthe1eyedGerman]

@@PRH123 only Atlanta has that but the rest of Georgia no so we always straight piped all our vehicles

[@PRH123]

@@SquirminHermanthe1eyedGerman wow, didn’t know, all of Maryland since the 80’s required annual emissions tests for all cars

[@SquirminHermanthe1eyedGerman]

@@PRH123 that sux

[@corgiowner436]

The GM system killed dual exhausts.

[@Ascotman]

yes, 1977 Pontiac Police "Enforcer" Lemans 400 4V with single exhaust! I owned two of them, could not top 110 MPH.

[@SquirminHermanthe1eyedGerman]

@@Ascotman yea even the Trans Am for '77 was single into one muffler & twin exhaust! Of course I ripped all that out & put headers & true duals on mine

[@mikee2923]

True. Nothing after 1974 came from GM with true dual exhaust. It was also the reason the Trans Am/Firebird went from using the Turbo 400 to the Turbo 350 in 1975. The Turbo 400 wouldn’t fit due to the catalytic converter. Anything Pontiac built with a 400 or 455 came with a Turbo 400 otherwise. My personal belief is Pontiac initially killed the 455 option in the Trans Am in 1975 because they couldn’t back it with the Turbo 400. When they brought it back in mid 75, you had to get the super T-10 4 speed. That remained true for 76 until the 455 was dropped all together.

[@CharredSteak]

3rd gen camaros lol

[@utuBrV1oI]

@@SquirminHermanthe1eyedGerman The Macho(lol) t/a came with 2 cats & no mufflers - i wonder if they were both GM pancake mufflers .

[@rpkietur]

we had a 1976 grand prix. one day all those beads just blew out the exhaust.

[@davidgagnon2849]

Like magic! Or was it because someone blew them out with compressed air? LOL

[@dj33036]

I can't believe the amount of overhang on the front end of that last Thunderbird

[@Santor-]

I know right? If they only made the hood a little longer, it could been real popular.

[@JxH]

Yep, they're rubbish at rock crawling.

[@joninpgh]

Crash protection. LOL.

[@marko7843]

Yeah, but it kept the wheelbase down to a decent turning radius. I've also noticed as I've moved to smaller cars over the years, with front-wheel drive, that my older larger RWD cars could turn tighter than the Turbo 325 or transverse FWD cars.

[@pcno2832]

Ford released a "safety car" video around 1971, showing their engineers grafting another foot onto the nose of an LTD or a Torino. The T-bird and Mark IV and V seem like production implementations of that strategy. Of course, by 1979, they had found a way to make the closely related new LTD with much less overhang and still pass the crash tests. That kind of engineering probably takes a while; I've heard that the front structures of some cars have 15 grades of steel in various places to create a controlled crumple in which the engine slides under the car. The overhang was probably a quick, dirty way to pass the testes until they got the crumple zone optimized.

[@sbf_fox2434]

The cross braces you mentioned are very similar to the ones used on the fox body Mustang convertibles.

[@jamestamu83]

We owned a 1972 T-Bird in a beautiful bronze color. I remember that the hubcaps were painted the same color. The car was just beautiful to look at, and it was the smoothest driving car we've ever owned. No modern vehicle can match it, IMHO. The 460-CI with 4-bbl carb was a real gas guzzler. I remember 13-mpg highway and "fill it up when you go to town" in the city. But I would love to have one today. Just so quiet and comfortable. When Jimmy Carter rolled out the 55-mph speed limit you felt like you were walking down the highway. That car was designed to cruise at 90-mph! Great channel and content!

[@williamholtonjr.8577]

55-mph became law under Nixon

[@carlc5748]

Pres. Nixon mandated the national 55MPH speed limit, effective Jan. 1, 1974.

[@skaldlouiscyphre2453]

Swap a more modern engine and the fuel economy will improve.

[@ChrisACiufo]

I had one too. But it probably didn’t stop really well from 90mph.

[@mikee2923]

The GM converter was a piece of crap along with just about everything they came up with during this era to control emissions. I think it was Hot Rod or Car Craft years ago took a colonnade car and replaced it with a true dual exhaust and the engine picked up something like 35 HP. A cheap set of headers brought the gain up to 50 HP. None of these things really did anything to curb emissions. In the mid 80s when emissions testing came to my state, I bought my first car a 75 Pontiac Grand Prix with a 400. By this time it was a well used up car. The converter was replaced with a test pipe. The exhaust rotted off so I bought a cheap set of 3 tube headers because the manifold bolts for the pipes were hopelessly rusted. All of the emissions gadgets under hood had previously been plugged with screws when they failed. I even had the heads milled to pick up some compression. But according to the emissions results which you got a print out of, that car with nothing emissions related functioning except the EGR valve, not cat, headers and dual exhaust not only passed emissions with flying colors, it would have passed for a new V8 Ford Crown Victoria. So tell me what was the purpose for any of that garbage that did nothing but give the American automakers a bad reputation for creating sputtering underpowered and unreliable vehicles that they never really recovered from?

[@davidam9454]

I remember at the time Mazda modified the combustion chambers of their 4 cylinder cars and sailed through the emissions test with better results than the converter cars. The problem was the big 4 were taken over by accountants. They looked at how to do it cheap, not how to do it best. The less gas burned the less emissions, the less government control. Remember the rest of what was going on at the time.

[@marckyle5895]

I did that to my Galaxie. Headers, cam, duals, 4bbl Edelbrock intake. Only thing I didn't change was the rear end. That 400 ran great afterwards. 16 mpg at steady 65 mph after the 55 limit was killed and it could pull a fully loaded U-haul trailer at 90 mph.

[@lsswappedcessna]

@@marckyle5895 16 mpg highway is wild for a 70s car. I bet with some gear ratio shenanigans you could get that to 20 or higher!

[@marckyle5895]

@@lsswappedcessna It was already a 2:75, one of those weird Ford 8.7" differentials. Had to get it fixed once is how I knew that. 16 was good. I started out with 12.

[@richceglinski7543]

Thanks Allen. I learned something I had never noticed before. I cut my career teeth as a mechanic working on this generation of cars. Was 1975 the only year for the single cat? A business man customer would drop his 75 MK IVat the shop before leaving on business trips and told me to drive it so it didn't sit on the lot at night. I was 22 and quickly found I preferred driving luxury cars over my noisy hot rod.

[@kevinsellsit5584]

My neighbors would question me on how much does a mechanic make now days...Porsche, Mercedes S600 god only knows what customers would say "don't park that here tonight, bring it home" ... Yes sir.

[@adamrodenberg1557]

With one side restricted, it would push more hot exhaust through the intake manifold heat riser passage to flow out the other side, heating the bottom of the intake manifold to improve fuel atomization, and allow faster warm-ups in cold climates.

[@gus473]

Ford's R&D was all over the emissions requirements of the Clean Air Act, including instrumentation to accurately measure NOx and SOx in exhaust. Manufacturers were close to panic over the possibility that the EPA wouldn't certify engines for sale without a reliable and reproducible method using a durable instrument. They made it, but just barely! (And they were ahead of the rest!) 😎✌️

[@xaenon]

Their early IMCO systems made their carburetors and distributors a nightmare to work with. IMCO was first mandated in 1965 in CA cars, and in 1968 it became a federal thing. In fact, part of the reason Ford replaced the 289 with the nearly-identical 302 was primarily for emissions reasons.

[@michaeltutty1540]

I had a 76 Thunderbird, and it did have factory catalytic converters on both sides of the exhaust. The uneven back pressure from one cat would be very hard on the valves in that engine unless the passenger side had much stiffer velvet springs to mimic the back pressure from the cat on the other bank. At Chrysler, cars with 1 or 4 bbl carburetors were able to meet emissions standards without a cat until the last year of the Plymouth Fury/Caravelle and Dodge Diplomat. Both offered a 4 bbl version of the 318 in Police Duty Package cars through the end of production in 1989. Volvo 4 cylinder cars with a carburetor were able to meet emissions standards with no catalytic converter. These, of course, are the Canadian market cars, which had to meet much less stringent emissions standards.

[@rightlanehog3151]

Adam, I will never look at a '74 Thunderbird the same way. 😁

[@user-ns9xq4bl4q]

These videos are great.... thanks and blessings....

[@douglasthrelfall5318]

Some cars had two different size cats in the ‘Y’ pipe, Dodge trucks and the Ramcharger had 1 large cat one the right side and a “mini” cat on the left. Fords used the honeycomb design which was more free flowing than the pellet type. I had a 1979 Mustang Indy Pace car replica with the 302 and C4 and a friend of my dad’s who was a engineer out of Ford’s tetaboro zone office gave me another nearly new cat from a 2.3 turbo and I got a long 1/2 extension a busted out that honeycomb bs and installed it . With the 302’s “sport tuned” factory exhaust, it was louder then stock and NJ’s yearly state inspection question the noise level from my nearly new pace car and when they looked underneath, yup, there was the (hollow) cat and it always passed emissions.

[@roger628]

The 1977-78 Dodge Monaco CHP cars had 3. Dual cats plus a mini-cat on the drivers side. Can be seen in the odd episode of Dukes of Hazzard when Roscoe flips his car over. Evidently the show sourced those cars from CHP police auctions.

[@ronaldkovacs7080]

Very informative. A lot of people do not know the intricacies if the earlier emission control systems

[@Guns_N_Gears]

My buddy had a Cutlass with the factory exhaust and besides the annoying rattle of the heatshield the floor was always damn hot

[@greggc8088]

Yeah, you had to be sure not to lay the ice cream you just bought from the grocery store in the passenger;s front floor board on the way home or it would melt. 🤣🤣

[@butchs.4239]

I'd expect the bonding straps shown and mentioned were intended to suppress noise from the ignition system.

[@RinoaL]

I'm surprised I saw this coming from your introduction, but then again maybe I know the industry too well. haha

[@ml.2770]

My father bought a new GMC truck in 1981. When he got it home he drained the beads onto the driveway and bought leaded gas. He didn't know how bad leaded gas was for people. It should have been ensured that unleaded gas wasn't more expensive than leaded when it was first introduced.

[@bobroberts2371]

Not to mention how leaded fuel corrodes exhaust systems, fouls plugs and increases engine wear. Leaded fuel has lead scavengers that are corrosive, this can also lead to cylinder bore / piston ring corrosion that will lock up a motor if it sits too long.

[@johneckert1365]

​@bobroberts2371 stop it 🛑, leaded fuel was MUCH better for engines.

[@curtislowe4577]

​@@bobroberts2371References? That sounds like a lot of 'everybody knows' urban legend stuff. I come from a do the recommended maintenance family. Even back in the leaded days we never had an engine suffer any of those failures, especially fouled plugs. My folks always got excellent service and long mileage from their cars. Tetra ethyl lead raised the octane and provided exceptional anti-wear for the valve seat area. One of the first changes unleaded gas mandated was stellite valve seat inserts for the combustion chamber.

[@bobroberts2371]

@@johneckert1365 Apparently you were never around engines running leaded fuel. Exhaust systems might last 3 years, spark plugs lasted 15,000 if you were lucky, an engine that sat for a year usually locked up due to the lead scavengers I mentioned. Lead was added as a cheap octane improver.

[@ml.2770]

@@johneckert1365 Leaded fuel was terrible for humans. The major reduction in the homicide rate from the 70s to now tracks with the phase out of leaded fuel. Engines can deal with its loss.

[@JimmyLoose]

5:00 GEEZUZ!!! That bumper gap filler looks like the swimming deck at the rear of a yacht! You could fish off the back of that thing!

[@prjndigo]

I had a 77 LTD2 with a rebuilt 318 out of highway patrol service in Florida, it'd been ret-re-ro fitted with three cats leading to a single pipe. The whole exhaust line was far too pretty to have been stock. 13mpg but could still pass emissions even tho I didn't need it to. (some shops had out of state testing gear)

[@carlc5748]

1. Honda had the CVCC engine, available to the public in 1975. GM laughed at their idea, so Mr. Honda bought a new 1973 Chevy Impala with a 350c.i. engine, ran it through emission's, passing it, with better gas mileage right to GM, proving that it could be done. 2. Mitsubishi had the MCA jet engine. I bought new, a first year 1979 Dodge D50 pick up (Mitsubishi) with this engine, and no catalytic converter, in California. 3. Subaru had the SEECT clean air engine, as well. No wonder, even back then, I knew that the Japanese automakers were going to take away market share from the USA automakers, due to their innovative thinking. At least Ford had an innovative approach, never knew that before, thanks for such a great Vlog!

[@JBM802]

The Japanese and the Europeans were restricted on engine sizes so they had to squeeze every bit of power and efficiency they could out of every cubic centimeter, and they were good at it! that’s why they had the better engineering. The big Three just made everything bigger without making it better.

[@carlc5748]

@@JBM802 Excellent point!!

[@stevelacombe5291]

Those Mark IV’s were better looking than any Caddy.

[@blue6gun]

My is300 had three of them lol. One upstream for each bank of 3 cylinders on the header and one downstream. It didn't mind me ditching the upstream cats but I had a harder time deleting the downstream without ecu changes or a stand alone ems.

[@tomtom1541]

What issues did it cause with the tune? I was curious cause I heard it might affect air fuel ratio. But I've only ever seen a p0420 code.

[@DarkAttack14]

Unusual that the primary cats did not give you an issue but the secondaries did, on many cars the secondaries do not even have o2 sensors post cat! Primary cats are usually a more sensitive area due to the primary o2 sensor being used for fueling adjustments

[@edwardallan197]

Utterly fascinating. I never heard about this, or saw it.

[@GorgeousGeorge525]

My youngest just got his 1st classic car (1976 Thunderbird w/460 big block) and when he crawls underneath to change his 1st oil, he will check this one-cat setup! Interesting topic!

[@SquirminHermanthe1eyedGerman]

helluva boat anchor for a 1st car! My aunt had a '74 460 that got about 8 mpg & in the mid '80s I had a '79 351W that got 12 mpg plus there was always some kind of issue with hers & mine but mine finally gave out when the crank pretty much exploded one day while I was driving to work so I sold the car for scrap metal, last Ford I ever owned

[@greenbassboosts8872]

Hard to believe it'd still be on there after all these years

[@GorgeousGeorge525]

@@SquirminHermanthe1eyedGerman he has a daily driver already: this is just a toy for him to learn from

[@GorgeousGeorge525]

@@greenbassboosts8872 won't know until we get the creeper under it. Only 90k on it, and the car looks original, but who knows

[@SquirminHermanthe1eyedGerman]

@@GorgeousGeorge525 oh thats cool, Im just glad he's got an old classic to fiddle with! My first was a '67 Firebird 326 4bbl that I got for $800 when I was 15 in '81 & at 16 I bought a '73 Plymouth Fury III Sport Coupe 360 4bbl for $300 & by the time I was a Senior in '84 I had a '78 Ttop Z28 that I got from a bank repo for the payoff of $1200! In '86 I bought for 1st new car, a Bandit II Edition Trans Am that I had until 1998! Man I wish I still had all those cars

[@Sedan57Chevy]

Gotta love Ford finding fun ways to cut costs! Some of the most expensive cars they made, and yet they choose to do this. I'm still also hoping for a video on their "wonderful" Variable Venturi carbs.

[@larryberry2436]

😂

[@arneminderman3770]

Great info ! Thanks

[@carrielemmon1549]

I had a 1979 Ford Ranchero GT with I believe a 351 Windsor engine. It was grossly under powered. We replaced the original engine with a 351 Windsor donated by a 1969 Cougar. All the smog devices were there, tho only to appear functional. The exhaust recirc pump was there, tho hooked up, didn't do anything, The manifold was modified to prevent vacuum leaks and the catalytic converters were removed and the ceramic catalyst was chiseled out and removed and the converter chambers reinstalled there by making them nothing more than resonator chambers (nice sound with Thrush Turbo mufflers behind them). The engine had yearly tuneups, and oil changes about every 4000 miles. This was before OBD plugs and cars had to be probed up the exhaust to check emissions. I bought the car in 1984 and the modifications were performed around 1985. It passed emission tests every year thru 1997 when I sold it and even beyond til the twit teenager that bought it totaled it. It also greatly improved the power and economy, averaging 22 to 25mpg hiway and about 17 or 18 city. I miss that ride.

[@carlc5748]

Could not have been a Ranchero in 1979, 1977 was the last year. In 1978, a Ranchero type vehicle was specially built, based on the new for 1978 Ford Fairmont mid size platform, called the Durango. Yours must have been pre 1978. You sure came up with a very innovative idea to get your Ranchero to perform better, I did something very similar with my 1975 Datsun pick up, that I bought new, to improve drivability, like what you did.

[@roger628]

The Ranchero was built until 1979.

[@patrickmurawski400]

To the low IQ here! Have a 1979 RANCHERO 500 THERE FULL SIZE FORD DUH!!!!!

[@carlc5748]

@@roger628 Was it still on the Torino mid size platform in 1978 and 79?

[@roger628]

@@carlc5748 Yes. 1977-79 were all the same.. You are thinking of the Durango. It was a Third-party conversion of the Fairmont Futura in 1980-81. The company that built it was National Coach of Gardena, CA.

[@PRR1954]

Bonding: In this era you could order a CB radio from the factory. Radio range can be a lot about ignition and alternator noise. No, we were not supposed to do long-range on CB but, ya know, the car shouldn't "bzzzzzz" on weak CB stations, man! FWIW, the '79 TBird w/351W had two very small cats right against the manifold stubs. I don't think backpressure ever bothered these ultra-mild engines.

[@xaenon]

they were ultra-mild partially BECAUSE of the cats.

[@jonathankleinow2073]

At first, I thought you said the pancake catalytic converter was filled with bees. But beads make more sense.

[@user-sv4so1tf5q]

Had several 'big 3' V8 boats. Loved 'em all! '06 Corolla my daily driver now. Love it even more!😮

[@recoilrob324]

Asymmetric back pressure on a V8 worked to push exhaust through the crossover passage in the intake manifold which heated the area right under the carburetor. This vaporized the fuel better and helped them run on a leaner mixture. Many non-catalyst engines had 'heat riser' flappers in one side exhaust to do the same thing by blocking the flow and forcing more through the crossover passage. Some of these were thermostatically controlled by a bi-metal spring while others used a vacuum can controlled by a temperature sensing switch in the cooling system. I'm SO glad all of the emission controls used in the late '70's and through the '80's are gone now thanks to Fuel Injection and better combustion chamber technology.

[@peterbedrosian622]

i worked at a lincoln mercury dealer for over 20 years they did some weird things to their cars like changing a camshaft and firing order on a 302 and windsdor 351 without changing crankshaft timing great video

[@DanTheMailman330]

My God, the mid 70s Thunderbird bumpers were fully.

[@trolleychai]

Among the vehicles I have owned was a '79 Bonneville that we purchased, brand new, with the pancake converter. At about 50K miles the engine became very sluggish (it was never a speed demon anyway, with the 301 c.i.d. motor, but it always ran very smoothly). When I took it to my mechanic, he laughed and said it was the converter, and simply removed the plug, shook all the balls out, and put the plug back in. The car had a lot more power after that, and it didn't make any more noise than before either.

[@Matt-ne6de]

the difference in backpressure across different cylinder banks must be chill as I notice that the saab B308E engine, a version of a gm v6, has "asymmetrical turbo charging," or that the turbo is only connected to the exhaust manifold from one of the v6 cylinder banks.

[@ProjectFairmont]

The Swiss cheese frame area is quite robust. Those transition angles bridging the the frame under the engine and supporting the suspension to the frame rails are two frame rails welded together. Having analyzed this on my own car these holes are IMO to minimize the collection of debris keeping them open. Boxed frames in general have a tendency to hold debris and potentially rot versus a C channel frame.

[@johnharper2016]

Bought a brand new 1977 Mercury Bobcat. Loaded. V6 engine and all the bells and whistles. First week I had both cats removed and replaced with straight pipe. Next eliminated the A.I.R. Smog Pump. Next re-jetted the 2 Barrel carb. Huge difference! That German made 2.8 lt V6 would sing. My buddy did the same treatment to his 1978 Mustang II, V6, 4 speed manual. Again, huge difference. Where there is a will, there is a way.

[@marckyle5895]

That was the same V-6 they used in the 70s era Mercury Capri and that car had a rep for being fun to drive. I would have picked the standard over the auto. You didn't need the 140 hp 302 when it was heavier than the 115 hp V-6.

[@jahnw1392]

I used to drain the pellets out of the gm converters and drive the car to get the remaining pellets out . The gm parts department sold a replacement plug kit that consisted of a piece of bar stock with a 3/8 threaded hole , a replacement plug , and a 3/8 bolt .

[@joecummings1260]

I used to change those pellets when I was a mechanic at Chevy long long ago. They came in what looked like a big coffee can. You opened the plug with a container under it to catch the pellets and tapped the converter with a rubber mallet until they all fell out. Then there was a plastic tube about 18" long that fit in the hole the plug came out of. You hooked a vacuum to the tailpipe and opened the can of new pellets and held it under the end of the plastic tube so it sucked them all back up into the converter while tapping it with the mallet so they all packed tight. when they all were in, you put the plug back in. Then you put the old pellets back into the can, sealed the lid, marked it as return and GM took them back. It was part of some periodic service, but I can't remember which one. I never saw anybody do it once the cars were out of warranty and never saw a private garage do it

[@martin-vv9lf]

I've seen it said the gm didn't give away the catalytic converter for the public good, it was a form of market protectionism as they had a monopoly on building them, can't recall fully but i think it was the internal components. basically competitors had to buy from them at a markup so by introducing the law they would have an unfair advantage.

[@johnrand93]

Adam, I don’t know if you’re aware but in 1980, (on the Lincoln’s) they had 4 cats, two pre cats and two main cats. I do know that whatever any of the manufacturers did, the smell coming out of any of my cars had ZERO smell, whatsoever. I know, if I ever buy a car that has any odor at all, I either put on a nos cat, correct the defective emissions part causing the car to smell or I re-bead the cat itself. I’m a stickler for an odorless exhaust, no matter how much power it robs the car of.

[@w.peterroberts9624]

Thanks for the video Adam. The government was forcing lots down the throats of the car makers then with the costly bumpers and all the emission requirements.

[@htimmermans1938]

Very interesting ❤

[@chrisreynolds6520]

GM had some strange ones as well. My 1983 fullsize van had factory catless duals but they had to run dual emissions air pumps and massive air injection manifolds to the factory tubular exhaust manifolds. In 2005, I swapped a 1990 Corvette aluminum head L98 TPI in place of that smog era junk engine. I bought a wrecked, low mileage car for $800 for a donor. The Corvette exhaust manifolds and cats were retained initially although I later put smog legal Thorley Tri-Ys for a G-van and even more modern 2.5" high flow cats on it. The TPI Vette engine had 80 hp and tq more with about 6 mpg better fuel mileage. That L98 gained about 20 hp and 30 tq with the headers/exhaust and I put a small Lingenfelter cam upgrade and SLP runners on it for another 30-40 hp gain. After upgrades it still ran with emissions readings that were near zero. EFI and modern monolithic cats were the key to getting more power, better fuel mileage and cleaner air in the mid-late 80s. The multi-point injection or even TBI was a huge step forward from a carburetor.

[@aliassmithandjones9453]

thank you for showing that 1972 t-bird! I saw one in an old photo on FB and spent hours trying to figure out what it was but eventually gave up. I knew it was a Ford product tho :)

[@joebutchko2223]

Going to guess the holes in the torque boxes and the presence of the cross bracing are related- trying to control where any flexing took place, and where it didn't.

[@EyesWideOpen61]

Isn’t there some way the engineers could’ve balanced the backpressure between the catalyst and non-catalyst side of the exhaust system, just thru pipe thickness or something

[@mopar3502001]

Great video. You should also do a video on Ford's thermactor emission system. That was another very interesting strategy.

[@arrowhead455]

That X-brace bolted to the frame looks to come from the Band-Aid engineering team 😂😂

[@failranch9542]

Ford’s was actually a flux-capacitor type. That’s the reason for all those grounding straps. It had to be very well grounded to get the turbo-encabulator effect going after startup.

[@tomm1109]

Thanks for showing the bumpers. The Thunderbirds and Mark IV always looked like they had way to much front end overhang in front of the wheels with those bumpers. I'm glad we got 1 good year in 72 of that bodystyle. Interestingly, the GM A body colonade style was supposed to come out in 72. I always wondered what a small bumper version of those cars would look like. If you can find any info it would make a great video.

[@63bbray]

Some California certified '77 and '78 Plymouth Fury/Dodge Monaco police cars with 440 V-8's wlth dual exhaust had 3 catalytic converters. One normal-sized converter in each exhaust with a small converter on the left side near the exhaust manifold. I was told it was needed to control excessive emissions when the engine was cold and the heat riser in the right manifold was closed. With the choke on and all the exhaust going out the left manifold the small additional converter would warm up fast and compensate for the rich mixture.

[@jrbpit1]

I’m not a fan of of over government regulation, but the air pollution devices mandated has made a difference. As a child of the 70’s and 80’s I can vividly remember the smell of unburnt gasoline going down the highway. When I go to classic car shows today and I’m around a running vehicle from the 60’s or 70’s all I can think is yep that’s what the 70’s smelled like. Also, I have a 2022 Mustang that has 450hp out of the factory, meets emission standards and gets 25MPG on the highway. How far we’ve come.

[@johnhickman106]

The X-brace was a structural upgrade to convertibles. If it was on any hard tops, it would redundant. Ford was still doing it to Foxbody convertibles through 1993.

[@OLDS98]

Thank you Adam. I liked and prefer bumper guards on cars. Some cars look awkward without them. I do miss them and I miss cars too as we live in and suve crossover world.

[@Mr.Higginbotham]

Thank you.

[@user-pr8zn6iw5t]

I'd assume the "H" pipe helped balance any differences in exhaust flow. A scavenging effect would help the choked flow of the converter side.

[@49commander]

The Ford frame design that came out with the "Quieter than a Rolls" 1965 were of the "rubber frame design" they were supposed to flex to reduce road shock and minor imperfections. Then Ford mounted a body that was built like a Unit Body from the Cowl on back. The entire dog house kinda floated on the frame and was loosely connected to the Body. This design really helped reduce Engine Noise being transmitted to the cowl. One side effect was you could see the hood and front end jiggle on rough roads. I am guessing the extra heavy front end on the T-bird and Continental just jiggled too much so some extra braces were added since these were premium cars. My Aunt had both T-Birds you showed! The Pre 5mph front end and the 1975 style. As a young kid I thought that 1975 T-Bird was the fanciest car in the world! Dad had a 1974 Dart Swinger which was a nice Dart but seemed so low budget! However, I wish we could had mothballed that Swinger since they are worth a good deal of money today!

[@xaenon]

That is a pretty obscure piece of information, my friend! Few people know about that. I am impressed!

[@49commander]

@@xaenon I found it in an old magazine when the cars were new. Plus an interview done later by a retired Ford Engineer who worked on the design! Ford wanted the squeak and rattle free properties of the Unibody with the Isolation of a Frame and Body! It' worked so well they used it till the end of the Crown Vic and Lincoln Town Car.

[@rbcrain2469]

I loved the Mark 4s still do!

[@jackierabbit450]

I swear the front end of some of those Fords look identical to the front end of Chrysler's from the same era, specifically the 1973 1974 Chrysler Newport...

[@ThePaulv12]

I'm a mechanic and I don't know why they did this but I can surmise. Possibly a bimetallic heat crossover flap in the driver's side exhaust manifold would activate when the engine was cold rerouting the driver's side bank's exhaust under the intake and out the passenger side when the choke was active. If I'm right (and there's the distinct possibility I'm completely wrong), most of the exhaust during warm up would then pass through the cat. When warm and measured at the tailpipe then with only one cat the emissions were within spec. Don't know if it's true but it's a good story lol.

[@patrickmurawski400]

Have a 76 Thunderbird has 2 converters! The frame would survive a nuke blast they were built solid!! And runs perfect!

[@edwardkantowicz4707]

Fascinating!

[@MoparTech]

My first car was a '75 LTD w/a 400, this was in 1990. I remember it only having a drivers side cat before the dumb kid I was at that time had a dual exhaust put on it.

[@rakninja]

it is very distressing to see cars that were 10-11 years old when i was 5 wearing "antique" license plates.

[@mrw417]

My 1975 Continental had a cat on one side (driver's, as I recall) and exhaust-side air injection from a mechanical pump on the other. It was a 460, super quiet and powerful. I don't recall any cross struts or grounding straps. It did have a lot of vacuum devices (headlight doors, climate controls, etc), so the engine bay was full of vacuum accumulator cans and hoses.

[@highrzr]

I believe the 1982 Ford Mustang GT had the same exhaust setup.

[@madmike2624]

I will never agree with the government getting in on design but who am I? Once again, Adam finds the best of the best obscurities and makes it captivating and entertaining!!!!!