GM's Strangest Big Block V8s: The Crazy 455s You Didn't Know About!

[@TomWilliams-z4e]

The essential purpose of the 2bbl big blocks was low end torque using oversized jetting. GM realized customer test drives were at low speeds where bottom end torque mattered most.

[@salninethousand2496]

Also, 2bbl = improved throttle response off idle and lower RPMs.

[@JW...-oj5iw]

The Quadrajet gave excellent throttle response at the bottom end for those willing to learn how to work the throttle judiciously. Getting the engine to medium RPM before engaging the huge secondaries results in strong transition to full power. A competent carb tuner can balance a Quadrajet to eliminate the Quadrabog reputation. My most recent engine build included a Competition Cams 292 and a Weiand Team G intake along with a Quadrajet and a nice HEI sparker. Given that combination, the torque leapt up at midrange RPM and rotated the axle nose up. That was unforeseen and required some refitting and bolstering. That combo was just a bit too much for streetability and I had to retire that car. Now it's been replaced with a bone stock C-20 in the longest factory configuration for 1975.

[@dmandman9]

Often the 2 barrel carbs got lower fuel economy than the 4 barrels when operated under normal conditions.

[@empireOfLove2]

@@dmandman9 Larger venturis for the same volumetric air flow always result in worse fuel economy, slower air velocity promotes less complete air/fuel mixing. See ThunderHead289, he put a lawnmower carburetor (with a very tiny venturi) on a ford 302 and got amazing fuel economy.

[@michaelbenardo5695]

Unless you used those huge secondaries a lot.

[@Sechott12]

I know a guy I met in the early 90s. He was building a hot rod 455 for his car. In the mean time, his family car blew its engine, it was a mid 70s Buick station wagon full size. He had no choice but to put his hot rod engine in that wagon. He embarrassed all rice modifiers who challenged him.

[@JW...-oj5iw]

Our neighbors had a T-Bucket powered by a Caddy engine. I wish it and they were still around.

[@JW...-oj5iw]

I built up my 350 in my '75 K-20 and it was a screamer. The truck was equipped with the granny 4 speed and manual transfer case. Those gear cases accounted for an incredible traffic clearing incident. I was working at a service station when a big truck hauling a big load stalled on the street in front of the station. Traffic got jammed up and the local police arrived to try to manage the mess, but that truck rig wasn't about to move. I had some experience with the 4wd truck and so I offered to pull the rig out of the street. I hooked my chain to the truck's front axle my rear frame. I engaged my front hubs and began to try to pull in 4 wheel high range with the transmission in first gear. The load was too heavy and my truck sat there pulling on the chain and bouncing up and down. After a couple seconds, I realized I needed lower gearing and shifted the transfer case to 4 wheel low range. At that point the power pulled the truck, trailer and tractor from the street and into the open parking lot where I could figure out what was wrong with the truck. Corrosion on the battery cables. Always remember to wash it off with blue window cleaner and protect it with original WD-40. BTW, I became a towing driver subsequently. I've cleaned a lot of battery clamps in my life. I know what works best.

[@scrocrates6380]

I'm sorry honey....I had no choice 😂

[@bendeleted9155]

Since GM used spreadbore 4-barrels, the 2-barrel was often bigger than the primaries on the 4-barrels. If you never got into the secondaries on your 4-barrel, you might think the 2-barrel seemed more powerful around town.

[@bendeleted9155]

9:15 perfectly stated by Adam later in the video.

[@catsaregovernmentspies]

Yes, until the late 70s when GM released the Dualjet with the same sized bores as the primaries on their Quadrajet.

[@tholmes2169]

But a Quadrajet would get better mileage exactly for that same reason, if you stayed out of the secondaries. My 350 Buick was factory with the 2 Barrel but I found a 70 350/4 off a LeSabre and took the intake and carb. I was getting 20 to 22 mpg on the freeway when commuting back to and forth to college in the 90s.

[@michaelbenardo5695]

That's why I prefer square bores.

[@Sheisthedevilyouknowwho-ft9we]

Yeah, I remember when I finally found this out, that if you didn't floor it, and open the secondaries, you can get better mileage with the quadrajet than the dual jet. (We had a dual jet here that was a quadrajet with the secondaries covered with a metal plate and it said dualjet on top 😂 it's been so long I don't recall how common those were). I don't recall what car it was, what rear diff ratio, onexof the writers at HPP with a 455 4 bbl years ago said you can get 20 mpg if you drive it the way he does. I was born '74, but I was the last of 6. My father only drove Pontiacs, and bought many used ones for my older siblings to drive. Bonnevilles, Grand Villes mostly. A few years after the 301 came out, he spent the next decade buying cheap used cars, some had 301s like my moms 77 Bonn or 77 GP for sis, but if it was a huge older Bonn or GV he put the 2.90 rear in it with a 301 he'd get somewhere for the good mileage. We might still have 3 301s here. When I learned this about the 2 bbl vs 4 bbl (I could have been learning so much from him 1980 through the 90s working on these '70s Pontiac but I wasn't interested at a young age), I wish I had known well enough to tell dad "no, don't ditch ths 455 or 400 again, you , me, mom, or the others, can drive gently, and get good mileage, just stay out of the secondaries". Just blow the carbon out on the 2 mile spur once in a while like they used to say. When I told other gearheads years later how many 455s and 400s my dad gave away for a song in the early 80s and later😫 they were like why ? He fell in love with the 301. I became more interested in working on my own cars later in life, and see some of this stuff that he did back then like why..why..why..(they had a 63 Bonn with a 4 speed , he took it out and put an automatic in it cause mom was huge, pregnant 😂, she said she loved driving that 389 4 bbl with the 4 speed before he thought he needed to change it). My uncle & my mom said he did a lot of unnecessary work on the countless Pontiacs he owned, but what the heck, you live and you learn. Mss you dad

[@townhall05446]

I had a 1970 Ford Country Squire wagon with a 429 2-bbl. Instant power when you stomped on the gas, no hesitation from secondaries opening.

[@miloswanson9646]

Back in the early-mid '70s, my folks had a pair of '68 Olds Delta Customs - 2-dr 'holiday coupe' fastbacks - both with 455s.. Mom's was the 365hp high compression 4-barrel, dad's was the low compression 2-barrel. Dad's 2-barrel car actually had more options on it - vacuum power locks, vacuum power trunk release, cruise control, rear defogger fan, and the 'halo' vinyl top. IIRC, the side trim was different between the two as well. Mom's had the more deluxe set-the-temperature AC system. These cars were geared for highway cruising at 75+mph, so when the Feds lowered the speed limit to 55, they actually got decent gas mileage. By decent I mean well over 18mpg - yes, with 455s!

[@GenXtra65]

I remember my first experience new car shopping with my father in 1970. I asked why we weren’t looking at 4 barrels. He said they were hot rods that needed Ethyl (premium) and we didn’t need one. We ended up with a Dodge Polara Custom (the luxury model). It had a 383 2 barrel. It ran on regular and moved that car quickly and quietly! Oh and it got 18 mpg.

[@PhilRacicot]

Funny, I just had a conversation with a friend about the Buick 2 barrel 455 of 1974 a few days ago! I just sent the link to my friend! I think it was also available in the Century/Regal that year (1974 was also the last year Buick offered big blocks in it's intermediates).

[@67marlins]

Excellent post. I'm a Ford and Mopar guy who always liked Pontiac and Oldsmobile too. Thanks for the research and presentation. By the way, I achieved 17.6 mpg TWICE with my 1970 Mercury Marquis, 429 2-barrel. Summer weather, highway driving.

[@marckyle5895]

My '73 Galaxie with the 2bbl 400 got 15-16 back when the speed limit was 65 and I obeyed it. But it had enough torque to pull a fully loaded u-haul trailer at 90. 2 barrels are nice if you get them set up with the jetting right and find a replacement with larger venturis! Fords went all the way from a 1.08 diameter 2bbl venturi to at least a 1.33, which meant about 150 (or more) more CFM.

[@warrenwinslow4266]

I got 18.6 out of a 460 Ltd landau 4bbl

[@67marlins]

@warrenwinslow4266 Wow. That's excellent. Pre- 1975 I assume ? ( I just read that was the beginning of catalytic converters.).

[@LongIslandMopars]

My 66 Coronet with a 273 gets about 12 mpg no matter what I do.

[@tonymaglio9376]

As a young g m mechanic in the eighties I saw variance of five ton trucks with two barrels big block.

[@gt-37guy6]

The 455 2 Barrel made it's way into the now highly collectable 1970 and 1971 Cutlass SX as well. Had a friend who owned a Metallic Blue one with a Hurst Dual gate shifter and white buckets. It was a really nice car....they only made 1820 of them. The 455 - 2 worked out pretty well in that car - even with the open rear axle it really felt strong and did well on the street in the 80s. I was jealous as I had a 72 Cutlass Supreme 350 4 Bbl.

[@bbsbcv]

My first car was a 1970 SX with the high-compression 2-bbl 455, dual exhausts through a cutout rear bumper and the 2.56 posi rear. This was back in 1983, when it was a basically forgotten model and nobody knew what they were. All I knew was that there was a "Rocket 455" sticker on the top of the air-cleaner. The first thing I did was buy a used factory 4-bbl intake and carburetor and replace the the stock intake. Great torque from that engine.

[@gt-37guy6]

@@bbsbcv Holy cats the top end on that car must have been 140 ish.... There is a Red 77 Regal out on Utube with a 455 Buick with 2.56 and that car holds a speed record in that class. 168 or 172 ...somewhere in there. It also pulls a 12 second Quarter with that rear end!

[@bbsbcv]

​@@gt-37guy6, yeah, I know I had it where the needle had wrapped past that 120 mph tick on the speedometer and was basically pointing straight down. But the real feature was how comfortably it could just cruise at 100 mph with no drama whatsoever.

[@gt-37guy6]

@@bbsbcv We must be living some parallel here, did the same with a buddy in a 70 GS455....same story highway gears, wrapped out top end until it was straight down. A GTO I was in with another friend just snapped the speedo cable at the same time the Kawasaki cycle we were racing also broke his! Unreal stuff - great to hear your Olds exploits....

[@robb1165]

@@gt-37guy6 I had a 70 442 with 3.73 gears in the 1980's. My bracket racer. It ran 142 mph in the 1/4 mile. Topped out somewhere around 170 mph at 8200 rpm. Rpm limited by me, built to probably survive 8600+ rpm.

[@kevinkoepke8311]

I've always thought it strange that Ford always called barrels venturi's, as in 2v or 4v. The three deuce setup was the best of both worlds. 2 barrel for cruising, and always having that extra power when needed. Thanks!

[@catherinecherniak8197]

best part about the big block v-8's was their sound -- you could feel it deep down in your gut. i miss that sound. eventually all we'll have is silent ev's. never heard sweeter music than a big block with a lopey cam

[@michaelbenardo5695]

Just grab a big block V8 car now, and don't get rid of it.

[@TheBighorton]

I had a '72 Pontiac Bonneville with the 455/2bbl. Enormous boat of a car. Fair amount of grunt up to about 30 mph, and then it just ran out of wind. Not slow, per se, but not as much power as you'd expect. Hit passing gear on the highway and you could hear the engine desperately dragging at that tiny carb.

[@ctblackwing56]

As a teen in the late ‘70’s, I got to drive my uncle’s ‘71 Delta 88 455 2bbl..car was dark brown, black vinyl top and interior..ac car..had gobs of power around town in the lower Hudson Valley/NY..I always wished he would have sold me that olds

[@meagain6889]

Thank You Sir!, I,m 54 and respect the content!

[@keeganandersson4281]

What Adam said about the 2 barrels feeling peppier at low speeds and 4 barrels at high speeds makes so much sense. Notice the ratio of horsepower to torque for 2 vs 4 barrel in the brochure. It means tq peaks at lower rpm for 2 barrel, and the extra hp of the 4 barrel can be felt at higher speeds

[@oldgoatroper7030]

I had a 72 Buick Centurion with a 455 2-barrel, and also a 74 Ford LTD with a 400 2-barrel --- no lack of power in either.

[@MrPoinzee]

My Grandfather bought a 1972 Bonneville hearse with the 2 barrel as well he also purchased a 1975 Bonneville with the 4 barrel after he died my mother inherited those vehicles and according to her the older hearse would out perform the younger one.

[@michaelbenardo5695]

No EGR, less exhaust back pressure, which means less pumping losses.

[@lmrk8441]

The early Olds weren't all that heavy on the HP but a beast in the torque dept.

[@kspegleg]

I own a 68 Oldsmobile Delmont 88 with factory 455 Rochester and a two barrel. It seems to have plenty of power. It doesn’t like RPMs though but low down cruising it is excellent.

[@steveaustin7306]

Had a BB 350 2bl in my 73 Buick centruian. Great car.

[@mkernen]

The 4 barrel cars likely had different cam grinds which would explain much of the HP gain over the 2 barrel on the same engine

[@robertlutgen7636]

Turnpike Cruiser 442 had a 2 BBL carburetor and 2 series rear gear. If you could keep your foot out of the throttle the Quadrajet it got better fuel efficiency. As you stated the primary circuit is smaller than the Rochester 2GC carburetor. A 2 BBL carburetor will give a better burnout.

[@marko7843]

Unfortunately, I think you are wrong at 8:24 when you say that we could just put dual exhaust and a four-barrel carburetor on the engine to wake it up... I had a 1973 Grand Am with a 400 2Jet, and put aftermarket dual glasspacks on it with a QuadraJet. I learned the hard way how much difference there is between the 2bbl & 4bbl camshafts... Short of tearing into the engine to replace the cam, I had to put high ratio rocker arms on it so it could use all the fuel from the QuadraJet. Cost me 3mpg on the highway, despite the fact that the front half of a QuadraJet is more efficient..

[@Flies2FLL]

Now I understand we are talking bout GM engines, but there have been a few Big Blocks from other manufacturers. Mercedes Benz built a 6.9 liter V8 in the '60's, and though it wasn't very powerful, it could sit at 125 mph on the German Autobahn for hours at a time, something NO American engine could do in stock form. It was literally an aircraft engine. Porsche built the 5.4 liter/329 cubic inch M28 V8 for the 928 car, and it has almost the exact same bore spacing as a Chevy big block, and for that matter a 440 Dodge. In fact, Arias in California has mounted 4 valve DOHC M28 heads on a 502 Chevy big block and the resulting engine will pass California emissions while making 550 hp all day long....

[@ecarroll3723]

I had a 1972 Pontiac Grand Safari station wagon with a 455 2 barrel carb.. When you got on it, it would spin the tires..

[@bluemule3891]

I hate you mentioning R McNamara, but love your channel. I remember the 455 2 bbl, weird ducks. They knew fuel economy was on the march, but still a torquey at low end around town, and towing naaaah not so great.

[@jameskerrigan2997]

Had 455 wild cat in 76 buick nice car plenty of power.

[@John-i3t9o]

What I find hard to believe is even with reduced compression and net HP ratings, big V8's back in the late 70's and 80's had horsepower less than a modern Honda 1.5 4 cylinder (2020 CRV has 190 HP). I've been told "it's all about fuel injection and computerized controls", but I find that hard to believe. And the idea that Shelby's and Hellcats can produce 600-700 HP from the factory is even more odd. (Along with insurance companies insuring these as old used cars with yahoo's behind the wheels)

[@michaelbenardo5695]

Before computer control and EFI, it was impossible for high horsepower and low emissions to co-exist.

[@michaelbenardo5695]

By the mid 50s, they were making more than that. They fell in the 70s due to EPA mandates, not because they were inefficient. Also, we wanted strong low-end torque, and high efficiency and low-end torque were not compatible with each other.

[@elainestamper3873]

If I get one with a 2v the very first thing I’ll do when I get time is replace it with the 4v, I have done it in the past with multiple cars and pickups and was always happy I did! I even did it on a 305 Chevy and gained a lot of power on a other wise totally stock engine

[@DanEBoyd]

That black Bonneville at 8:49 looks like it could be yours Adam, with those turbine-ish Colonnade Lemans wheel covers. And the nice looking red Electra convertible @10:33 is about identical to one a family in my neighborhood owned for quite a few years from new. Theirs had a white top, and I don't remember the interior color.

[@alexmerlin4764]

I drove a Pontiac 389 2bbl and it was nice and peppy) by modern standards all of those cars are dog slow on a highway, so some extra bottom end torque ads a bit of a joy into city commute) And the reason behind "why?" is likely familiar to you as a finance guy, they must've decided, that they can save some extra buck, putting cheaper equipment under hood judging by the existing demand)

[@mark_osborne]

Yes the 4 bbl Q-jet had triple annular discharge boosters = better mixing and atomization which made for lower emissions and better fuel economy

[@ericheld4382]

My 67 Ford convertible has a 390 2V and it runs great.

[@corgiowner436]

Interesting that the final OLDS 455 in the video has a dual snorkel air cleaner but only one side has cold air induction.

[@LyndenMcconnell]

I had a 1968GTO with a 400 two barrelcarb with a stickers hoping a 10:75 compression. Ran like crazy! Weird

[@LyndenMcconnell]

Still have the engine.

[@nixencooper2705]

Towing...put a 455 2bbl in a square body...ultimate tow vehicle....500 ft lbs at 2400rpm

[@duayneveer8229]

Hello Adam I've owned a few early 70s B bodies My 71 Bonneville had the 2V 455 like you said nice in to and really not bad on the highway too But uphill and passing seemed like a real chore sometimes Lack of horsepower was obvious but just for daily driving I could live with the gas milage I also had a 73 Catalina coupe 400-2V Performance was very similar

[@michaelbenardo5695]

It was not because of a lack of horsepower, it was because of super-tall graring.

[@NorthernChev]

Because for years consumers mistakenly thought 2-barrel meant “fuel economy”. And what auto manufacturer back then would dare screw with public impressions if it got in the way of sales; despite the fact that spread-bore 4-barrel carb’d engines got better MPG if you just stayed out of the secondaries.

[@prairiestateautoresto]

Chrysler has the 361 2bbl, 383 2bbl and the 400 2 bbl.

[@Patrick-xd8jv]

Yes, I actually knew about them and even drove several.

[@marcwiart5657]

I have to say Dad had a 455 2 delta 88 and a 460 4 ltd. The Ford was a real dog and seemed to be harder on gas the Olds had poor top end as expected but otherwise.. pretty nice responsive mill. The 460 was a slug everywhere. I remember thinking finally a 4 barrel big block again! He had a 1967 383 magnum Dodge before the other two cars so in my young motor head you can imagine. The old Polara had more grunt in the windshield wiper motor than the Ford. The Olds while slow was not totally embarrassing in traffic 😁

[@NorthernChev]

What’s with the picture of the small block 2-barrel intake sitting unbolted on top of a big block engine (0:56)?

[@izzydizzy1115]

Just to add, I had a 69 Caprice with a 396 with a 2bbl making 265hp

[@SamuelGoolsby]

The 455 4- Barrel Station wagon gave a great kick if you needed to pass on the freeway. Would have more power that my V 10 fuel injector 6.7

[@tomconner5067]

Correction Cadillac had 3 different displacements of their masterfully designed big block, the 425, the 472, & the 500 cid V8s

[@insulman100]

I owned several Pontiac 455s and not one of them was a big block

[@SpecialAgentJamesAki]

I believe the olds 455 4 barrel has a bit more duration on the cam vs the 2 barrel.

[@tonybeef1142]

I get 10.56 mpg 😂.1987 Cutlass, GM crate 350 H.O . Deluxe .I am happy.I got 10mpg when I had the 305 in it.😢

[@tabbott429]

I put low compression 366 dump truck oval port heads with tiny valves 1.84"/1.66" on my '68 396/402. The low end torques is much better.

[@enerrivers4392]

My gr8 aunt had a new Buick Estate wagon with a 455-2bbl. I never drove it, but worked on da Express way. My dad had a nu 73 Electra coupe with da 455-4bbl. Dat I drove, nice power.

[@kclefthanded427]

Anything less than 4-barrel on big blocks is criminal

[@michaelbenardo5695]

Not everybody is a hot rodder.

[@markkimball1569]

I wonder if the TA and Gs Cutlass chevelle were 😮 seated for power how we can trust the power was underrated across all of them ? Either way the big blocks were reliable for the bigger cars !

[@kevinjokipii4260]

I know Pontiac didn't have big and small blocks in terms of bore spacing, but the 400 came with a 2 barrel, and it was a high deck engine in contrast to the low deck 301 and 265. If the 2 barrel reduced fuel use, I'd hate to see the 4 barrel MPG. I could *see* that gas gauge needle moving on my Catalina.

[@kc9scott]

Actually, the 4-bbl generally are more fuel-efficient than the 2-bbl, since most of the time on the 4-bbl, you're only using the primaries.

[@kevinjokipii4260]

@@kc9scott I can believe that. I had a couple 4-barrel Mopars and if I could resist opening the secondaries, the Thermoquad with small primaries definitely behaved differently from a two barrel

[@timmcquerry6068]

I must have missed something, what did Robert McNamara have to do with Fords having 4bbl.s?

[@lb3418]

Dual-Jets for the win.

[@danielleclare2938]

Chevy did a 427 2BBL... maybe. I think in the Caprice.

[@cbobscountrybunker2312]

Ford 460s did come with 2bl carbs the early ones

[@elainestamper3873]

Richard Holdener dyno tested a Big Block Pontiac 2v vs 4v , 4v had 50 HP more, Hard to understand why any car company would knowingly and yes they knew, choke the the engine of its true power by putting a 2v carb that worked great on a 239 flat head Ford on a 390,429 or 400,455.

[@wlm2618]

Strange in this case means that it was not on a Chevy. Many of those 455’s left plenty of Chevy’s behind on different tracks.

[@ClumsyCars]

A guy was going to sell me an olds 455 rocket drive train for $350 to put in a 85 jimmy. Me being young never scrapped up $350...

[@Snuckster2]

another weird 'big block' was the 2bbl 400 used in the turnpike cruiser Oldsmobile's

[@61rampy65]

Didn't those use something like a 2.41:1 rear axle ratio? I haven't thought about those in quite a while.

[@Snuckster2]

@@61rampy65 yep and I think it was the first GM engine to use temperature controlled intake. Crazy enough I got 19MPG once in my tuned 68' Electra with 2.73s and the AC running on a trip to Bodega Bay from Sacramento. Usually got 9-11MPG in the city and 15-17 on the freeway with it. Miss that car a lot

[@The_R-n-I_Guy]

The best thing about cars of that era is you could buy a 2 barrel, single exhaust car for decent money. Then convert it to a 4 barrel and dual exhaust later. Modern vehicles are pretty much as is. There's no modifications you can do to them to change the performance. Unless you have the money to add or upgrade turbos and have the computer programmed. Not much you can do in your driveway. This is why I never want a modern vehicle. They're all overly complicated, cookie cutter crossovers with too much unnecessary technology

[@jamesengland7461]

They're not as hard as you think to modify, but then they're not so sandbagged that just a dual exhaust adds 50hp either. You can still swap a cam on an LS or Hemi just like old times.

[@embiggens1]

I think there's two sides there. With modern, forced induction cars, you can get huge gains with just a tune, no hardware necessary. I picked up over 70hp with nothing but a tune. A gain that big used to require a lot of hard parts. I do miss the old, inefficient engines with so much untapped potential, but it's not all bad these days. Yet, anyway.

[@michaelbenardo5695]

Not only that, if you DO find a way to modify a modern car, it won't pass smog.

[@dwightvoeks9970]

All you have to do is throw a tune on modern cars and some you can instantly gain 100hp and better fuel economy.

[@tabbott429]

I bought a gryphon programmer for my 2006 F150 4x4 long ago 375$ It was tuned professionally by them and i just plugged it in and reprogrammed the computer with a couple clicks. I gained 2-3 mpg (100 miles more per fillup) and a MUCH better/responsive driving experience. Shift points and timing were optimized and made the stock tune feel pathetic.

[@bendeleted9155]

By 1974, you could get the "economy" 455, touting 9 MPG instead of 8. 😂

[@sergioleone3583]

Well, it was a 12.5% increase in economy! ;-)

[@larrynorsworthy8582]

😂

[@salninethousand2496]

That's 12.5% better fuel economy, which is actually quite good.

[@towgod7985]

9mpg @ $3.55 gal. MOTHER that hurts!

[@towgod7985]

@@salninethousand2496 ROFL!

[@DSP1968]

I always enjoy these engine episodes, Adam. Keep 'em coming, please!

[@bw6378]

Yeah 99.9% of the time the secondaries are closed. I used to find Qjets with stuck secondary butterflies from lack of use surprisingly often. lol

[@curtjeziorski350]

True. If Those secondary butterflys were not shiny ass clean that means they weren't used enough!

[@cigarsgunsanddiesel8032]

We called em Quarda-bogs around here... mine actually performed decently, because I drove it like a madman!

[@noscwoh1]

With those big heavy beasts, torque is the name of the game. HP is fine for top speed, but torque gets you off the line. Nobody was racing those sedans with the 2BBLs, but acceleration was fine for Interstates, and as you said, zippy around town. I've driven plenty of Quadrajets, and love them to death, but Rochester's 'Duojets' were special too.

[@madmike2624]

I could not agree more!!! Great idle and wide-open sound with the air cleaner flipped, it had a great sound!!

[@paulfrantizek102]

A 2V Big Block has good low end torque and good throttle response. In most applications, that's enough.

[@jimmyaber5920]

I commuted until recently around the north side of DFW area. There were loads of 420 hp escalades, bmw x5m, mercedes gl 63 amg, etc. with much more than 420hp and for the mostmpart they were only using 35hpnto go slow in the left lane while on the phone. Definitely the 2 bbl big block buyer.

[@jameswaltersdorf2783]

We had a 68 Delta 88 when I was growing up, and it's incredible now to think how powerful that engine was. What I don't remember was having to use premium gasoline. Was that because regular gasoline was leaded or higher octane generally? We had the car until I graduated from high school in 79 and I know they started using unleaded gasoline, so I don't know if we ruined the engine or something. One thing about 60s Oldsmobiles was you could always tell that one was nearby because the exhaust had a particular, lovely throaty timbre.

[@dermotthompson2115]

Nah. Why throw away useful power for no good reason?

[@bhayescampbell]

The 455 c.i. With 365hp in my 1970 442 4sp convertible was quite fun. Wish I still had it!

[@opera93]

Yes, thanks…. Interestingly, I opted to a 1970 DOdge CORONET 500//383/ DUAL , AUTO./ no AIR Conditioning ,@$3100.00…….( switching from FORD, as Dealer could not give “ test Drives” for BOSS MUSTANG: passing on a70 Challenger Triple Green/ 4 SPD/Se RT/ Loaded every option((my baby BROTHER remembers vividly)

[@Mike-jv4rz]

Worth a small fortune now ...

[@salninethousand2496]

Also of note, the 2bbl engines usually had a smaller cam and heads/valves, which also accentuates lower RPM response.

[@madmike2624]

great point!!!

[@WhittyPics]

I heard if you keep your foot out of it, a 4 bbl carb will use less gas than a 2 bbl

[@jamesweidinger1117]

If you keep your foot out of it, a four barrel carburetor IS a two barrel carburetor.

[@StringerNews1]

It's true, especially with a spreadbore like the Rochester Quadrajet. If you're drag-racing, using high numerical ratio rear ends, and launching near the redline, then CFM matters. Everywhere else, other things like fuel atomization and ram effect play a much greater role. A 4-barrel carb is more efficient all over, compared to a 2-barrel.

[@kc9scott]

And the same engine with a 4-bbl will have slightly higher MPG rating than a 2-bbl.

[@StringerNews1]

@@kc9scott in fact, a somewhat popular modification after the Arab oil embargoes was to disconnect the vacuum line on vacuum secondary carbs, to keep the secondary barrels (of a 4 barrel carb) from opening. The impact on drivability was minimal, as maximum air flow is only needed at maximum load. Everywhere else on the power curve, the higher velocity leads to _better_ performance. Better fuel atomization is more efficient.

[@dmandman9]

It’s true because the primary barrels of the 4 barrel carbs are smaller than those of the two barrels.

[@DaveSoCal]

I remember racing my buddy in his 1968 olds455 and I in my ‘79 trans am 403/auto. I couldn’t shake him !

[@dansmusic5749]

Both Olds engines.

[@DaveSoCal]

@@dansmusic5749 yeah but I was in a Trans Am not a 4 door land yatch 😭

[@DeepseaSteve]

Had a 77 with the 403. Ok for cruising but no race engine

[@dansmusic5749]

@@DaveSoCal More detuning from smog controls, I assume.

[@michaelbenardo5695]

60s cars were rocket fast. 70s cars were not much better than late 40s cars.

[@larrynorsworthy8582]

Those big engines got 16-18 mpg if driven right if they had tall gearing.

[@haggis525]

My first car was a '70 Olds Delta 88 Custom 4 door hardtop... it had the 310hp 455 - 2V and I found it to be an excellent driving car! It may have been lower hp but it was plenty torquey and I never felt it lacked in any situation. I think she ran near 500 lb-ft so... no worries! A good friend of mine had another '70 Delta... a ragtop with a 350 - 4V and mine was considerably quicker. I think the 350 - 4V also had 310 hp but less torque. Both very nice driving machines... the glory days of the General!!!

[@Flies2FLL]

Ford produced a lot of 2 barrel "McNamara" big blocks with two barrel carburetors. On the surface it sounds stupid, but when you get into the engineering, it makes tons of sense because these make tons of torque which people like while not using tons of fuel or producing tons of emissions. -Really, the American auto companies should have advertised this back in the 1970's. "Big but slow turning equals efficiency!", just like the high bypass ratio turbofans on modern airliners. My spouse is from Belgium, and when she first came to Flori-Duh, we had my mom's '89 Bonneville SE to take down to Key West. This car had a 3800 engine and was fast off the line, yet it ate 9 liters/100 km despite being the size of a Mercedes Benz S class on the inside. She fell asleep on the way down because the 3800 only needed 1800 rpm to do 70 mph and the relaxed sound and the soft seats lulled her.... "I'm not sure why this isn't sold in Europe!" I remind her to this day about this statement. "You picked an American, we are pragmatic first".

[@The_R-n-I_Guy]

I've never driven anything with a big block. The biggest engines I've ever owned or driven were GM small block 350s, and my 77 Dodge Adventurer pick-up had a 360. I've always wanted a big block car. A 1970 premium fuel big block GM would be my top choice. But really, any big block over 400 cubic inches of any year or make would be great

[@StringerNews1]

You'd better hurry, or you'll miss out. I grew up on big blocks, and just recently bought an '86 460 CID Ford truck, just to have a taste of big block life one more time. Now the '86 motor doesn't scream like the 460 in my parents' '69 Lincoln, but it's still a big block, and fun to drive.

[@joeskeptical4762]

*You haven't lived until you have taken a mid 60s Cadillac through a highway on-ramp at full throttle up to 90+ mph. Smooth, steady and pulled like a rocket.*

[@donreinke5863]

@@joeskeptical4762 My ex-girlfriend and I installed a 1975 Cadillac 500 in a 1981 Fleetwood Brougham that blew up (of course) its stock 368 ci 8-6-4. In the lighter post 1976 body it was an amazing performer, and virtually a bolt-in swap. Took it out one night on I-70 east of Denver, and it seemed like it would never stop accelerating. We left the 200-4-R overdrive transmission in it, had no idea how long it lasted.

[@jnywd8450]

As an old fart, I've rolled around in a few big block cars. Some stock, some built. They put a lot of extra wear and tear on the rear tires.

[@carscloseup]

I know it’s about big blocks, but I have 400 Chevrolet small block with a 2 barrel. I agree they feel peppier around town and for most driving conditions you’ll not get into the imaginary secondaries…

[@fscalamita7730]

Both fascinating and interesting ! I love Oldsmobile engines period. Have a low mile classic ‘76 Cutlass Supreme with a 350 4bbl. Smooth and dependable!

[@davidwinslow3614]

One of the most anemic Chevrolet was 69 Caprice with a 396 -2 barrel. A terrible combination! There’s a road test video that confirms how bad it was.

[@roger628]

@@johnz8210 I still maintain something was wrong with that car. It couldn't have been THAT bad!

[@Lucille69caddy]

@@roger628 I concur. When Bud Lindemann said “it couldn’t punch thru a wet tissue”, I about lost it.😆

[@GeekGinger]

Back in the 80s one of my sisters had a 70 Bonneville with a 455 2bbl. It had a very diesel-like power delivery. Lots of low end but ran out of breath early. Not that you’d spin up your Bonnie very often 😂 I don’t know about how or why but it was definitely a 1970 not a 71. 🤷 Maybe someone retrofitted it during the gas crisis.

[@DanEBoyd]

If you're not going all out, to high RPMs at Wide Open Throttle, a two barrel carb will still provide a nice snappiness, when taking off with a little quickness.

[@61rampy65]

My girlfriend had a 69 Olds 88 with a 455-2v, and it was a blast to drive! Monster low-end torque got that heavy beast going pretty quick, and even on the freeway, there was power to spare. All you had to do was put lots of gas in it!

[@joesmithjoesmith4284]

Back in the 70's when I was a teenager, the shop I worked at had a 68 Pontiac Catalina with a 400 2bbl, and a 67 Olds Delmont high compression 425 2bbl we used for parts runs and delivering customers. They did awesome burnouts 😁 Especially the Olds with the open differential. From a stop the right rear tire would spin up so fast it only took a couple seconds to shift in to 2nd and keep on going!

[@marcanthony854]

I miss those days!

[@izzydizzy1115]

I can still see the smoke from you burnouts!

[@jamesgibson5876]

​@silasakron4692 do you realize Quadra jets only had two cfm ..all q jets ..either 750 or 800

[@mnbalfour1985]

People want lots of horsepower without understanding that having lots of torque is what makes a car with a big engine so effortless to drive.

[@AliceEmpireBreadfan]

I almost purchased a Catalina wagon with a 3 speed on the tree and a high compression 400....but it had a 2 barrel. Always thought it was an odd choice but I believe those wagons only optioned a 4bbl with 428 in a Bonneville wagon. I should've bought that wagon but it'd be sitting with a RAIV camshaft, aluminum Kaufman heads and 4.56 gears. You know, because what else do you do with a station wagon.

[@michaelbenardo5695]

Wow, a 400 with a manual trans! I sure would have grabbed it!

[@60andover-timetotrain-join89]

I had a 1968 Olds Delmont 88 with the 455/2 barrel. That car was so ugly it was beautiful

[@bme7491]

I was 17 when my Dad bought a 1969 Olds Delta 88 with the 455 and 320HP and GM400 tranny. I got to drive it a few times and I remember how smooth yet powerful it was. If I remember right, I think he paid around $4200 for it.

[@joeskeptical4762]

*Doesn't seem strange at all, most of these 455 cubic inch 2 barrel cars were cruisers driven that way, Such car buyers liked strong torque right off idle, infrequently going above 4,000 rpm. Even Cadillac owners were unlikely to push the car hard at higher speed, but when that happened the Caddies, especially with the mid-60s 429 and 472 engines, could move well and sustain 90-100 mph easily. Even if this was not done often, it was expected for the high price. The performance difference between a 2 barrel and a 4 barrel of the same car and engines was only noticable if both versions were driven hard back-to-back.*

[@Seabee_Camper]

If you look closely, the Olds 455 2 barrel had only 10 fewer ft-lbs of torque compared to the 4 barrel version. Around town, the power felt the same. I mean, how many people rev'd an Olds to 5000 rpm?

[@albertsmith6016]

The 1969 full size Chevys had a 396 2 barrel as a optional engine.

[@markg7030]

Yes 265 horsepower. It was not a screamer but you got those 396 badges on the fender.

[@marckyle5895]

@@markg7030 bragging with nothing to back it up

[@gerryvandepol7630]

Had a 396 2 bbl in a 69 C10 3 on the tree work truck plain jane zero options..

[@ONTHEEDGEFRED]

I was going to mention this where ole Bud.Lindman did a review on one of those Impalas, , with the 396 2 barrel,l said it couldn't get out of its own way

[@DustinBaerwolf-kv9jx]

You forgot about the 396 chevy 2 barrel 265 hp. at 4800 and 9.00 compression

[@madmike2624]

spot on!!

[@jverrelli1]

My 1969 caprice 396 -2 barrel would smoke the tires no problem

[@jimmyaber5920]

Ford had a 429 2bbl, and AMC had a 2 bbl 401. I had a 1974 IH pickup with the AMC 401 2 bbl (and Dodge 2wd front suspension). I think the 429 2v was a 70 or 71 Mercury.

[@mikee2923]

Starting for the 1971 model year, GM capped compression ratios to 8.5:1 in all engines for compatibility with the coming low and unleaded gas.

[@ronniedale6040]

In terms of carbeuration more air velocity through the Venturi the better the response. Now this said the q-jet was designed around this principle. I suspect that in terms of total vehicle price making a quadrajet was quite a bit more expensive than a 2gc. That’s probably all the explanation there.

[@rightlanehog3151]

Adam, Our '73 Caprice Estate had a 400 V8 with a 2 barrel. Therefore, an 'Economy Olds 455' sounds like a fine idea to me as long as I can get it with a dual exhaust.😉 I have also driven cars with 1 barrel carburetors that made me dream of an upgrade to a two barrel. 😁

[@georgewetzel4380]

Why dual exhaust?

[@rightlanehog3151]

@@georgewetzel4380 Dual exhaust provides a measure of extra horsepower and better fuel economy by relieving back pressure without the hassle and expense associated with 4 barrel, high compression engines. In the old days there was often a difference in compression ratio across the range of V8 engines . The Economy 455 would have run on regular fuel. Then as now, you save money with cheaper gas.

[@IowaBudgetRCBashers]

My brother had a 69 firebird with a 350 2bbl. He put a 4bbl and dual exhaust off of a 455sd 73 firebird on it. It went from barely getting out of its own way to smoking tge tires around tge block, and that was a 2.73 rearend and a powerglide

[@gailmrutland6508]

*I had a pristine 1959 Buick Electra 225 convertible, white with red leather black top, and the 401. 325 hp / 445 Ft lbs of torque and the 2 speed Dynaflo slush glide transmission. Punch it you smoke the tires, and you would chirp the wheels as it came out of low at 55MPH. TOO FUNNY.*

[@dbx1233]

I had a Oldsmobile 425 big block that was balanced and blueprinted and it had a lot of torque. I love big blocks.

[@JeffK.]

Thank you for the informative article. I especially enjoyed seeing the pictures of the big blocks sitting in spanking clean engine compartments. It brought back a lot of memories from decades ago.

[@adamtrombino106]

I had read about 455 2bbls, but have never seen 1. I did have a friend that had a 69 caprice that had a 396 2bbl, which i found rather strange. But then too, all chevy sb 400s were 2bbls. Alot of ford truck hd engines were also 2bbls, like 352s and 390s. Maybe buick was trying to respond to the gas crunch in 74? I can't imagine it would get all that better mileage even with a duece. I had a 383 2bbl in a 69 fury lll sedan that was indeed peppy around town even with 2.94 gears. But it was still horrible on gas.