HOW TO: CARB YOUR 500 CADILLAC

Q-JET vs HOLLEY (ROUND 2) CARBS, INTAKES & MUFFLERS. FULL RESULTS
CHECK OUT ROUND 3 OF OUR 500 CADILLAC MODS (THE OTHER GUYS). AFTER ADDING HIGH-COMPRESSION (EARLY SMALL CHAMBER) HEADS AND A BIGGER CAM,THE CADILLAC WAS MAKING SOME REAL POWER. CHECK OUT THIS SERIES WHERE WE COMPARE THE Q-JET TO A HOLLEY (AGAIN), TEST A CARB SPACER, SINGLE PLANE INTAKE WITH A DOMINATOR AND THEN YANK THE (RESTRICTIVE?) MUFFLERS!!

[@markmenner6922]

I've been running quadrajets on street cars for years. A lot of people replace them with holley's because they are easier to tune. If you have a car or tuck that you drive long distances to car shows or power tours the quadrajet is hard to beat. The drivability is excellant and I've found the fuel mileage to be better. And there's some NHRA stock eliminator cars going really fast with quadrajets.

[@testpilot6456]

The Q-jet is much maligned & misunderstood carburettor ,ford even used it on their cobrajet ,if you understand them they can produce good economy & power.

[@ThePaulv12]

@DropDstar You're a man of class and style!

[@VORTECPRO]

Yes the Q-Jet does work good on my NHRA stocker but.....................your forgetting one thing, it doesn't use a mech fuel pump, it uses a unstreetable Magna fuel fuel system with 25 lbs forward fuel pressure, with out this type of fuel system you would never be able to launch the car with out running out of fuel.

[@thefinalroman]

@@testpilot6456 It's a piece of trash and luckily everyone knows that and gets a Holley

[@idletime]

I'm a Carter AFB fan myself. I've worked on my fair share of Holley carburetors but always preferred Carter. 1 carburetor I always liked and thought was really cool and always had good luck with but never could understand why they didn't upgrade them from polymer to aluminum is the venerable thermoquad. I also agree the Quadrajet isn't a bad carburetor overall and when you learn how to Kuna with a vacuum gauge they're a pretty good carburetor overall I just never got the hang of rebuilding them. While I'm thinking about it I will mention the biggest piece of shit carburetor I have ever have the sad Misfortune of messing with was Holleys attempt to copy Carter with the model 4011 ( I think if I remember right). And just for fun I do think the Predator carburetors are interesting to say the least and effective for that matter just not the most readable carburetor for sure

[@dannoyes4493]

Have you ever thought about naming you channel "The Enthusiastically Happy Engine Dyno Guy Who Never Sleeps"? BTW, great, great content.

[@richardholdener1727]

Seems long-but I like it! I sleep between dyno runs

[@Cradletothegrave67]

I run a 507” Cad in our 73 Cutlass bracket car, forged piston, H Beam rods, Cortney’s 76cc Pro Comp iron heads, 2.25/1.90, full roller rocker. Isky .660 / 260 @.050 solid lifter cam with EDM lifters. Bulldog single plane ( the tall one) and a QF 1050 dominator. It will drag a 3700 lbs Olds in 4000 ft DA into the 11.0s at 120. Leaving at 2000, shifting at 5500 all day long. And it does it with a production block, crank, and head castings. It’s fun and something different. “THE OTHER GUYS “ 👍🏻😎

[@johnparrish9215]

I didn't know about the altitude correction part of the Cadillac Q-Jet, that was very interesting.

[@ComfortablyNumb1969]

It was on more than the Caddy Q-jet. My parents had a 1974 class C motorhome that had a Chevy 350, that also had the APT adjustment.

[@chrisrye9128]

Worth consideration over fuel injection conversion with altitude compensator. Far less expensive even with a new/remanufactured Caddy Q jet. 🤔

[@ThePaulv12]

Some Thermoquads had it too.

[@jordanwiley4582]

It was a 75/76 only thing, for the most part. In 77 most carbs did away with it again, and by 1981 they were all computer controlled with a mixture solenoid, TPS, etc. 1990 was the last year, the 307 Olds in station wagons before the upsized roundy b bodies came out.

[@ComfortablyNumb1969]

I stand corrected. The APT adjustment that my parents motorhome had was different. It was a manual adjustment, that adjusted the primary metering rods, and was not the automatic system seen in this video.

[@Allianceoffroad]

Edelbrock needs needs to make a Performer RPM package for this motor!!...Aluminum heads...RPM air gap intake....matching cam

[@michaelangelo8001]

Seriously... The heads are the sticking point. The ones available now are just too expensive. It's cheaper to build a stroker BBC.

[@danawilkes6174]

Edelbrock can make Chevrolet 409 heads, and not these!!! That is Edelbrock for you...

[@ghostrt1608]

@@danawilkes6174 ...yeah, u got a point

[@biscuitboy3617]

You can use the Performer RPM Air Gap for a 429/460 Ford on the Caddy. The port spacing and several other dimensions are either the same, or very close. I've seen this before, I think it's 'Cad Company' that makes an intake adapter kit . I've seen a 500 Caddy with a nice polished tunnel ram for the 460 Ford installed on it.

[@michaelangelo8001]

@@biscuitboy3617 The experts tell me that the Fordy intakes don't perform that well when adapted to a Cadillac engine.

[@asambi69]

I'm a sucker for big inch motors so i love this stuff.

[@Scootermagoo]

We discussed this last video, the carbs should be the same powerwise if the a-f is right. The biggest difference is the smaller primaries on the q-jet for drivability. One advantage a holley has is 2 fuel inlets, which is the biggest limitation on a q-jet. Holleys are built as universal racing carbs and q-jets were designed for street driving. If you have never driven both, a well tuned q-jet has better throttle response compared to a holley. the holley can be tuned more for rich lean on paired cylinders and can be made to run better on single plane intakes and so on. If were going to discuss big carbs. The engines only going to pull x amount of air, but with a carb unlike efi the bigger the throttle opening the worse the response is.. So the dominator looks cool might make a little more power but it's gonna run like ass on the street on such a mild combo.

[@matthewwalsh8795]

RICHARD!! I'm glad you dove into the Quadrajet brother, I've been building them CLIFF RUGGLES PERFORMANCE style for years, he's the best and most comprehensive Q-Jet expert I've ever researched, his Cartech book on the entire line of Quadrajet carbs is phenomenal, a must read for anyone who touches them.

[@johnb7430]

Love the info. The monster caddy has come to life but, Come on now... tell us how much VACUUM and BSFC. These big azz motors are street driven and mostly in bigger cars. Give out how well the combos will work on the street.

[@puffkendrick6850]

That was the one of the reason most 500s came with a hydro boost brake system

[@Bolton115]

@@puffkendrick6850 The reason Eldos came with Hydroboost has nothing to do with the ample idle vacuum made by those old 1970s cams, and everything to do with competition-Rolls Royce had a camshaft driven, dual circuit brake pump system like on an aircraft. Cadillac, as the DeWar 'Standard of the World' trophy recipient, had to come correct in this area. I've worked on the Rolls Royces back in the day.. quite an interesting system, each wheel had two physically separate calipers because there were two physically separate brake systems. One driven off each end of the camshaft of that engine which, coincidentally, Rolls Royce licensed the design of it from Cadillac. Hydroboost was a better, more reliable system.

[@danawilkes6174]

I have ran many of the Q-Jets and the Performance Series Thermo Quads over the years, and most worked very well. I even ran Willie's Kendig carburetor a few times. I loved the "Spread Bore" idea. Better throttle response and gas mileage...

[@stuartcookie133]

i have rebuilt countless Quadrabogs as they are usually called and have NEVER seen that altitude adjuster! Learn sumthin new every time i watch Richards videos. Thanks Richard!

[@richardholdener1727]

Glad to help-It was new to me too!

[@TheDynotuner]

Very glad to see detailed testing on the factory mountain motor 500 c.i. Caddy. But due to the super low rpm range I'd Love to see the 750 Dominator used. We found with the destroked Fords that stayed Under 6000 they loved the small throttle blades of the 750 Dominator

[@asjmpickle]

You're making me want a 500 caddy over a small block Chevy

[@pjmccoy4216]

I'm thinking a can in the 235/238 with .580 lift would be a great street can. Allow you to rev out to 5000 but still have all the peak power in your normal driving range say from 2600-4500 would bring many meant smiles per gallon of gas.

[@kellyjones841]

Great video and info Richard, real world parts and work. Thanks for the quadrajet knowledge, Courtney!

[@travisabrahamson5092]

I would love to see street demon carb . Has nice tiny primaries and giant goggle valve secondaries. I've only run them on sbc so far but very nice street carburetors.

[@jimhodges3471]

As the owner of a 500 cad in an 80 El Camino I am loving this. Thank you Richard. Come on Eldelrock, make an RPM air gap

[@mafosa9563]

a good 3D printing co. could make a prototype to use. just to see if it will be worth it. just a thought. larry

[@interst8erj968]

What did you do for headers?!?

[@thelaneman]

What gears are you running in the dif?

[@jimhodges3471]

@@thelaneman 3.55 in a ford 8.8

[@richardfinney3179]

You should contact speedmaster engine and component's tell them to make a airgap manifold for the cadi mo I called them and we need more guys badgering them before they will move on it, tell them about roller cams ,distributers,headers, tall valve covers ,if I was gonna build another cadi mo I would offset grind the crank and use big block Chevy rod bearings with a 7,100 long rod , I've used them in big Chryslers motors up to 514 and I've had good HP out of them speedmaster makes some good stuff ,not like the old pro comp stuff the new director of the company was edelbrocks old director this company is doing some great things I've been doing business with them for 30 years the new stuff is way better then pro crap ,

[@finnroen2334]

Dual plane with full divider wall, divided spacer and Dominator would be interesting.

[@BruceLee-xn3nn]

Now you got everyone hunting caddie qjets

[@thisisyourcaptainspeaking2259]

I'm running a Thermoquad on my 455 Olds, took the Holley off and gave it to a stranger I didn't know. I wouldn't hesitate to run a Quadrajet but didn't have one handy at the time and when something runs great I tend to leave it alone.

[@liljohn3877]

If you had center dump headers(Sanderson), I'd love to see those against the long tube headers and stock manifolds. From old reading, it sounds like even junk homemade headers are an improvement over the stock manifolds.

[@willieshaw2522]

I'd run the Q-jet on the dual plane - power is close to the Holley, and just love the Q-jet sound.

[@timtaylor6147]

I have a Chevy Qjet from a 67 truck application It uses an APT screw under the primary rods to fine tune the part throttle mix I worked mostly with qjets Easy to tune but a pain if your in a hurry I was the electric Qjet guy at my first dealership job plus all the other emission carbs from 70s and 80s Still have tuning parts hanging around Great carb

[@austindoud273]

Someone really needs to hook a ras pi to an electric q jet w/ wideband 02 and closed loop that bitch probably be a sick setup

[@michaelangelo8001]

I have a pile of those electric Quadrajets here, and can't figure out what to do with them.

[@deanstevenson6527]

Michael Angelo : Use them as dual Qjets. MCS is great. Everyone understands pulse width modulation on EFi, but not on Feedback Carter Thermoquads and Rochester Quadrajets. Why, why, why?.I.e.a.o.....

[@michaelangelo8001]

@@deanstevenson6527 Oh, I have a SBC M/T cross ram already modified to accept dual Quadrajets. I'd love to put a couple of these on it, but who has time to build the electronics for such a capricious one-off application?

[@Bolton115]

Great series! Just curious, have you had any experience with the FiTech or Holly four barrel carb bolt on replacement fuel injection units? I'd sure like to see some dyno runs of how those systems work. The RV conversion crowd loves them-they don't leak, they self learn, and guys I've talked to say they no longer have to downshift into second when driving their old GMC motorhomes up I90 towards the Summit. I know that's not a dyno test, but real world, they seem to generate a lot more tractable, streetable power versus a carb. I haven't run any of these EFI systems yet, either, so that's why I'd like to see some dyno test action. Either way, thanks for the Caddy engine love!

[@richardholdener1727]

A 4-BARREL THROTTLE BODY WON'T USUALLY ADD POWER COMPARED TO A CARB

[@Bolton115]

@@richardholdener1727 Having extensively tuned the old fashioned way-jets, springs, needles, distributor advance weights and springs-was thinking that entering the modern age of computer controls might get more power out of less time futzing.

[@wesbafguy]

Courtney is the man. Please thank him for the info!

[@deanstevenson6527]

Wes Beaman : (and from down in the moonshine haul area of the deap south...New Zealand. Hearse and Hell Pizza territory....much love)

[@TheSamcram]

I love this series so much because I’ve got a 1970 Cadillac with a 472 big block (the shorter stroke 500) and it’s basically helping me plan out what mods to do to mine to make it a mean machine! Thanks for doing this official dyno series Richard!

[@the-dullahan]

"Hey guys, I'm here with Courtney, he's going to tell you what's different about the Cadillac QuadeaJet. But for fun, I'm going to run some dental drills in the background whenever he tries to talk."

[@dinkchow]

Why did GM/Rochester contrive such an over engineered carburetor.I'd spend my $ on a Holley b4 a quadrajunk pos.

[@jasonhooey5677]

Single plane intakes time after time just dont "work" on street motors. And a good dual plane will work in higher rpm anyways

[@michaelangelo8001]

The Performer is what I use. It's the best street manifold on the market right now. There is also a tunnel ram available though...

[@adampatterson707]

How much power can you get from the factory intake manifold? Some 425s have an aluminum open plenum intake manifold. What would 500 do with one of those intake manifolds? On a couple of other things, grew up with Q-jet carbs and we learned how to fix em. I have a Q-jet on a 4.3 in my firewood hauling truck and it works great. Old school turbo mufflers all the way. There is something about the sound of a healthy engine with a set of Thrush turbo mufflers that just warms my soul and puts a smile on my face. We'll never be able to thank you enough for all your hard work and dedication.

[@michaelangelo8001]

The factory intake works a lot better than you would think...

[@Bumblebee4788]

425 manifold runs uphill, I replaced mine with a hogged out carb flange 472 manifold and made more power!

[@adampatterson707]

@@Bumblebee4788 I have a 425 and the TH400 transmission. Both for $100. I know my 425 has the aluminum single plane intake manifold. I'm hoping to maybe learn a bit to see if anything can be done with a 425. That 425 would smoke the tires in the old coup it came out of.

[@ricon.i474]

It would be nice to see how a efi carb like the holley sniper would preform

[@vintagetintrader1062]

Does you family ever see you since you started your channel? You a a video making machine let alone the time it takes to build these engines at times.

[@timothybayliss6680]

I know the ls adapter intake test failed to impress, but Ford 385 intake adapters have been a staple for years with these engines. There is also way more intakes in both CJ and standard port sizes available. That's maybe something to think about.

[@angelovasilikos7980]

Very impressive this motor is such a monster! I would definitely use the dual plane but I would also like to see this thing love to at least 6500. Is that going be a next test?

[@hotrodray6802]

Requires rods etc. BOOM

[@Tegridynews]

I'm a Ford guy and I would rather watch that motor be a boat anchor for the Titanic to save it from the iceberg but I'm here watching this video because your cool

[@thereluctantgearhead4544]

Pretty narrow minded huh, that's gotta suck being stuck in that little box. I'm a GM guy, but I like Ford's too.

[@garykentner7557]

I have a 70 nova with a 500 Cadillac I have tried many carbs over the years I settled for a 800 cfm Holley double pumper spread bore it performs best of all for raw brute power the Q jet worked nice for Streetability and fuel economy but that Holley kicks but for full on tire churning performance. My nova runs 11.90 with 3.08 posi I have a Dana 60 locker 4:11 I’m guessing it will run somewhere in the 10 area I have a modified hogged out plenum with a spacer it sings to 6000 max built the motor in 93 and still going strong as ever with no oil consumption still has 55 psi oil pressure more guts than ANY big block I’ve ever built or owned that was naturally aspirated get one you won’t be disappointed the weight is between a SBC and a BBC it’s wide and use an Eldorado rear sump pan have fun

[@JohnH.-qp6fb]

My first time with a Cadillac in my own car. I've built 2 for customers years ago. These things are a brut ! Both were so cheap to build and so dang reliable. Both get 17 mpg on the hiway at 2,200 hilly terrain. Cam, 800 holley, big valves, edelbrock. That's it. Guy's that ride in this thing just start laughing when the pedal goes down. Best engine I've personally ever had.

[@ts302]

Love the Caddy 500! Next intakes to test is the BoogieMan Single Plane Intake AF71475, and a tunnel ram. A quick google search, I found adaptor plates to run any BBF 429/460 intake (www.pricemotorsport.com/html/body_ap-23__intake_adapter_kit.html) on the caddy.

[@kimmorrison9169]

love this test but 12 to 1 compression would be a deal killer.

[@RUBIZEN]

"Carbed" it? Damn near killed it!

[@azlandpilotcar4450]

Could someone get the best of exhaust performance by having mufflers with no constriction in the exhaust pipe? Maybe a Y pipe with four mufflers for the configuration in this engine? The Freiburger/Dulcich exhaust tests on Enginemasters seemed to suggest to me that it might just work...

[@blueridgemountainprepper2166]

I think I love how yall started pulls way down low, I'm a sucker for big torque way down low

[@bobbyshaftoe]

Velocity is King below 6K ...small butterflies, long runners...

[@sstevocamaro]

I’m going listen to “Be Thankful for What You Got” by William DeVaughn as soon as this ends 😎

[@DSRE535]

Q JETS are awesome, basically the most adjustable carb ever made and i build a lot of them for performance, i like the drivability

[@thefinalroman]

It was garbage.

[@DSRE535]

@@thefinalroman only if you have no clue what you are doing, they make edelbrocks for the simple folk

[@thefinalroman]

​@@DSRE535 even in 2020 the Quadrajunk strikes again kzbin.info/www/bejne/b16woa1qYq1rkMU

[@mattrodgers4878]

thefinalroman maybe you’re just not smart enough to figure out what’s wrong and make it work correctly? How many MILLIONS of Q-Jets were built? They worked very well for something you call garbage.

[@thefinalroman]

@@mattrodgers4878 U crazy all the quadrabogs are rotting in junkyards where they belong. The cars are begging for a Holley....

[@gmcnelly2468]

Maybe Edelbrock could make some small chamber cylinder heads too??????????????????????

[@01fxdlse]

Learned a whole bunch about cadi’s thanks!

[@pancudowny]

I think it's time to try self-learning TBI on it... because Lord-knows the factory put EFI on the 500 near the end! ;)

[@jamesreeder5316]

I have used spacers and I think they do increase power. But aren't you using a bigger holley I thought you said earlier that it was a 950? And if so it's not quite even ad your using a Qjet 800. I may be wrong.

[@bernielehman8288]

Buick with Rochester please 12 sec pull to check fuel starvation

[@Sebastianbartledoo]

put a 1 foot carb spacer on it and see what it does

[@thelaneman]

Poor man's tunnel ram!😂

[@thereluctantgearhead4544]

Probably would need to just leave the Jets out too.

[@thereluctantgearhead4544]

Could tie a little monkey to the Engine and train it to dump fuel down the carb as needed for extra enrichment under high load conditions.

[@MegaScott]

Edelbrock might sell a few dozen intakes a year for a 500inch Caddy. No way is that an economical number to justify producing an intake specific to a certain combination. i bet with stock un-ported heads the performer works just fine. The other thing is this, small carbs on a short floor dominator style big runner intake? The speed of the fuel and air mix shooting out the bottom of that smaller carb smashes right into the floor of the intake and then very slow speed air going to each cylinder. With a smaller carb on that dominator style intake, you need a 2 or 3 inch open spacer to give the airflow a chance to round the corner and make into the runners. IMHO.

[@benwingo6675]

The Q-jet we're good in their day, the Holley stold their thunder, the Holley is so much better on all their circuitry low speed and high speed , the tuneibuilty is superior to the Q-jet hand down. The Q-jet just gives up so much during it tranistioning from the front primary's to the large secondary barrel's you lost the race for that reason Q-jet you would not see them in serious competition. They do offer a great sound of power but their fall short in demand.

[@SurlyMike]

I'm loving these Cadillac videos. One of my old auto shop teachers in high school, Mr. Millar, had one set up on and engine test stand with open exhaust and we had used it to learn set engine timing and things like that. Most of us were 15 and that was a little intimidating at the time. None of the other shop teachers really cared to hear that thing fire up so many times a day. I think when I was a senior one of the other classes sneaked in and bolted some mufflers to it. I always loved that engine and when I acquired my 66 impala back in the early 90s I had since dreamed of swapping out the 283 for a Cadillac 500. I was really impressed with the numbers on the previous video with the high compression iron heads, that's something a guy can build on his own without too much trouble I bet.

[@SurlyMike]

@Peter Britt this was in AZ in late 80s early 90s, my older brother had the same teacher a few years before

[@bartpang]

It needs a chrysler long ram intake.

[@JohnClutch1]

I dont know the specs on the heads. And Im pretty sure your choice of cams was based on them. So with that, I dont think the motor has enough cam/heads for a dominator. The Quad and 4150 seems to be plenty and cant imagine that bottom end being spun any harder than it already is.

[@superduty4556]

I'll take all those shitty quadrajets off everyone's hands.

[@dondotterer24]

Glad it worked out great for the Q-jet. 74 jetsis a big change using the same primary metering rods. Hope it dont load up at idle.

[@kevinjohnson9372]

My opinion is the dual plane worked and best sp grind the numbers and markings off and pant it blue like the rest of the engine then install that engine in a caddy with a stockish air cleaner that has been modified for dual snorkels and send it

[@joekingrey1423]

Love the big Caddy...now it's time for some Boost !!!

[@JohnClutch1]

Also, whats the volume ratio between the headers and the collectors before the mufflers? I bet 1.25x collector volume would be the hot ticket.

[@iiNgONYaMa]

Do you have a link to the vacuum diagram for the 500 q jet?

[@dangerousfreedom4965]

So it likes the duel plane more, do to the motors low RPM?

[@erenzoscroggins8056]

Great information Richard... And for those who don't know they're are some Aluminum heads for the Cadilac that been out for years Caddy power going up💪🏾💪🏾💪🏾💪🏻💪🏻💪🏻

[@hotrodray6802]

He is at the Caddy specialty shop. YeeeeeHaaaaaw !!!😎😎😎

[@raylaux8295]

Power piston spring changers for a change. Oh, this guy don't get that

[@glennmanchester5696]

it sounds so weird not revving it above 5 grand like you normally do

[@scottbeckman4887]

Great video, can't wait for the Buick

[@brazenhammer3307]

i wish more performance parts were made for my 425,

[@rodneybynum8104]

Did you pick a winner for the H.P. guess ?

[@kimw9340]

Tunnel ram On the Cadillac ! Do it now 😄

[@american4890]

My comment is that when you went to single plain the hp is catching up to the torque 🤟🤙👍🤝🙏 peace

[@hackfabrication139]

Can't wait until you add..... BOOST!!!!

[@wakjob961]

I love to know what car those wide a$$ headers would fit in ;-)

[@scotthatch4653]

Built for the Dyno

[@LunarOutlawsGarage]

Keep up the great work. 🤘

[@Steinmetz1]

I have a 500 bored .080 over. .650 lift roller cam roller rockers, ported aluminum small chamber heads with sniper efi. I'd love to see something similar to my build. I have the single plane because it looks cool but might switch back to the dual plane maybe ported

[@make-it-work4u]

I wonder if anyone can prototype print a air gap manifold

[@JosephDudeson]

Definitely. Basic shape. Heat is the issue. Carbon fiber nylon is expensive to proto with, could prolly just mill some aluminum quickly. That's a good idea though.

[@jordanwiley4582]

Quadrajet is hard to beat upto about 500hp or on a daily vehicle. There are literally 1000s of combinations of jets, metering rods (primary AND secondary), as well as secondary hangars (how far in the secondary "jets" the rods hang, secondary jets are just a hole, they aren't actual jets) so its more difficult to get just perfect. But, my personal theory still holds. A qjet can and will run with the best of em if you put the time in.

[@thefinalroman]

it's garbage kzbin.info/www/bejne/b16woa1qYq1rkMU

[@thefinalroman]

@DropDstar The quadrabog is legendary as a mess that leaves u stranded with sub 10mpg when it does work. No wonder the quadrajunk died along with the 305 dog motor...

[@jordanwiley4582]

He's probably just mad because a well tuned qjet 305 whooped his Holley topped 355 lol

[@jordanwiley4582]

And that link you posted was on a REVIVAL 72 CUTLASS THAT SAT FOR 33 YEARS WITH OLD GAS. He lives in my state, he drove that thing 300 miles home and has been daily driving it for a month. Cant do that with a holly or edelbroke carb. Hasn't even been rebuilt.

[@thefinalroman]

@@jordanwiley4582 Open mouth insert foot. It died..... kzbin.info/www/bejne/l3m7n36vmNh9eJo

[@VORTECPRO]

Learned something about the Cad Q-Jet. Richard, you need to explain to the people when this engine makes 560 corrected HP its really about 420-430 observed or in the room HP in a 24.50 baro, I know you don't want to confuse people but it needs to be done.

[@hotrodray6802]

All dynos are corrected to sea level power..... Its industry standard

[@deanstevenson6527]

VORTECPRO : He continually and carefully explains this. Especially to Ford guys ( we get Buck shot hurt when a GM or worse, Mopar, or worse worse, an AMC handz it to us on a dyno. Any thing with a D in it. Or an M. Or a C....ouch. This snow flake is Melt Ting....)

[@deanstevenson6527]

VORTECPRO : Welcome Mark. A shout out to you....your head porting work and Gross Reported SF 901 hp is a credit to your handiwork and total commitment to honesty and transparency in reporting.The key here is you and Richard, Westech and the Courtneys kind of SAE Gross dyno testing and head porting or other mods is the Only Game in Town. As Richard will attest, Chassis dynos with a set loss converted back "should" be a better system of flywheel net power determination, but engine, tire and trans heat soak and counterweight losses are not constant or linear, yet the 300 or 600 rev per second speed factor is universal and SAE Gross SuperFlow 901 and 902's are repeatable to the horsepower using the aggreed SAE Gross Correction factors.. Gross SAE hp Dyno testing is a great thing, but the certified DIN or SAE J spec net is not repeatable unless a full exhaust with the sterner humidity, altitude, temperature and barrometer and full underhood air temperature, heat stove and air flow restrictions are included. Thats a huge amount of work. You have to drop the drive shafts or tires or put on a mock 100% factory engine bay and wind tunnel it with similated air flow and full exhaust. And do uncertainty and repeatabilty tests. Its all or nothing. For your info, The idealised shift between the two SAE Gross and Cerfified SAE Net readings is 1.14 to 1.16, historically, but on engines with cool air indiction or CAI packages or using dropped header pipes, it can be less or more. Specific to 5 liter Trans Am and SCCA and 7 liter Drag pack cars in the late sixties, and Fords in particular, The Peak power RPMs were also fudged so a dual quad non competition G code 289 Tunnel Port made 390 hp gross at 6000 rpm but was rated at just 240 hp gross at 4600rpm "down the curve". In a similar way, a Cool Air Induction package could turn a Cobra jet or Super Cobra Jet 429 into 430 hp gross but was rated at 370 or 375 down the curve. Cam Benty at Popular Hot Rodding in late 82 then discussed this return to fudging SAE net figures when the 2bbl Mustang 5.0 GT and 82 F bodies came out and did flat 16s or less with 157 to 180 hp net engines. engines.Gross hp Factory fudging and the huge logistical problems with replicating the certified SAE Net figures mean the idealised 1.141 to 1.161 difference between SAE Gross and SAE net is variable. Down here, a 300 hp Cleveland 351 US M code we used from 1970 to 1973 could be up to 390 hp gross without the 6150 rpm rev limiter, and at 6500 rpm or 340 to 350 hp net at 6150 rpm, depending on Shaker intake package and rev limiter. All iron intake engines, no EGR, but 3310 Holley 4bbl and similar K code 310 degree or 505 lift 300 degree cam. So your 1.30 to 1.33 factor would have ment Ford Australias Gross Rating would have had to have been 442 to 520 hp. This is wrong. The big stick SAE Gross to SAE net factors are just 1.141 to 1.16. A 1969 Pinto made 112 hp SAE gross but 98 hp DIN net on the Ford West German Cologne dyno. My 1958 Vauxhall Velox 138 cube six with 7.8:1 compression made 82.5 hp SAE gross, but just 72 hp SAE net. Summary...the Gross to Net figures are a lot less than a third off..Our Australian 14.4 second 265 Hemi Charger E49s with triple DCOE 45 Webers were factory rated at 306 hp at 5300 rpm SAE Gross, but made 295 hp SAE net at 5600 rpm on Leo Leonards Timaru New Zealand truck dyno. 1.04 difference. And thats how the Gross to Net conversion goes on Muscle Car engines or 2 liter Pinto sh!÷ boxes. A final summary. The factory Dearborn 155 hp SAE Gross 250 1bbl six made 102 hp SAE net on the Geelong Ford Australia dyno. 1.52 factor loss. So it varies a lot. I'd say use the generic SAE Gross to Net conversion. The US factory ratings from 1968 to 1971...they were accurate, but on some engines, adding a super restrictive tin hat cleaner and 1-7/8 inch exhaust system really kills power,exactly that much. That's where the 1971 verses 1972 1.3 to 1.33 factor drop came from, often 1.52 on the 250 and 302's. Its not accurate. Lastly, the net figures on a hydraulic cammed 11:1 1971 and 9.4:1 1972 Euro spec left over US Vin M code de Tomaso engines was 330 DIN net at 5600 rpm and 310 hp DIN net at 5400 rpm, but the same engine in the 1970 US 351 4V 1971 Ford Falcon GT made just 300 hp gross in Australia and the USA. The correction Factor was then 0.91 at worst, or 1.52. And that means Im not comfortable with a 1.3 or 1.33 SAE Gross to SAE net correction. 489 hp SAE Gross is generally 425 hp SAE net +/- 4 hp net. But not always. Richard has discussed this at length in one of his videos. It depends on all those ancillaries. This is Not Engine dyno Verses Chassis dyno or Flywheel HP vs Rear Wheel horsepower EG 1 @ kzbin.info/www/bejne/sGOplaeIl55nntk but Cold Air Intake, Fan, Accessories. What are they worth? kzbin.info/www/bejne/r3mrfXd6p66Wm5Y A 400 hp net Parnelli Jones Boss 5.0 gives 480 hp SAE Gross with the factory accessory drive and headers with cats on a SuperFlow 902, a factor of 1.20. So theres a huge issue with SAE net to SAE Gross hp factors.Taking the acessories off, it will easily push over the 500 hp level.

[@dangerousfreedom4965]

Please show the before and after power numbers together.

[@smileychavez8093]

Hey Courtney Smiley here in Belen New Mexico you have to let me use that engine for my black 70 Deville lol Courtney has been to King Cadillacs since I was a kid

[@richardholdener1727]

Courtney and the gang know how their Caddys

[@alfgotl]

Make a 302 lt1 engine. It's basically a 350 lt1 with a 4.3 lt1 crank n' rods

[@kensbackshop6399]

Q JAYS all the way how about a tunnel ram ???????

[@duramax78]

Richard I have a option of a lq4 for $200 or a ls7 block for $1300, I wanna make 600hp Na can you please tell me best route, (cheapest) to get to 600hp.?lq4 has bottom end, whereas the ls7 has a bare block.? Please help me with this problem.

[@richardholdener1727]

600 hp na with a 6.0L takes a lot of stuff ($)-cheaper with boost

[@bobbyshaftoe]

The TORQUE! >500lbft at 2k!

[@pablojanski.2559]

Pull the Qjet over an 11-12 second pull and see if bowl capacity keeps up with engine demand..

[@richardholdener1727]

That is a limitation

[@baby-sharkgto4902]

I'm fn LOVING this series

[@timecklund7685]

Good job testing at very low rpm. Useful info.

[@bcbloc02]

My 79 Cadillac was fuel injected and loved to act up and leave you walking.

[@calvinevans8305]

Cad 500 with tunnel ram or belt driven intake manifold.

[@hotrodray6802]

Hoping to see that belt driven intake !! 😱😱

[@dondotterer24]

To get real tricky with the exhaust you can make what I nickname swirl chambers like David wizard has used in his testing.

[@glennmanchester5696]

vizard

[@danieldimitri6133]

All of the quadrajet literature I've ever read says they don't take fuel pressure well. The needle and seat area is a big factor and perhaps the smaller seats do take good pressure but it's generally recommended to use a bigger (but not over sized) seat with low pressure. There are different floats with longer or shorter fulcrums etc so you can experiment for the best combo if you're racing superstock or something. The ho 305 motors tended to have pretty good secondary metering rods and there are probably a hundred mods you can do. The type of carb you choose shouldn't make a difference on the Dyno. On the street might be a different story but as long as you don't go too big with the holley it should be fine.

[@glennmanchester5696]

what ?? every q jet i ever ran liked more pressure than any Holley almost ten psi w out over powering the needle and seat easily and you want that little bit of higher pressure because of the small fuel bowl it has to keep up w fuel use under wot I was surprised to see the q jet take all that over 5 psi like the Holleys could handle it ran great w the stock fuel pump from a tbi and a fuel pressure regulator w return line never a hiccup not once did it ever starve and this was a big cubic inch thirsty motor a 455 pontiac and the 800 cfm carb it came with in 1978 in a 1990 chevy obs pickup truck it was a blast w the turbo 400 and a shift kit in it the carrier bearings didnt care so much for the shift kit lol nor did the u joints but they settled in when I replaced all of it at once even had a limited slip carrier installed w a 373 :1 ratio for a 4500 lb truck it was pretty fun and tires were sent to tire hell on the reg lol 2nd gear sitting still spinning at 90 mph burnouts were well smokey Imao

[@glennmanchester5696]

oops it says 455 it was a 400 trans am motor

[@michaelblacktree]

An altitude compensating carb? Neato!

[@Martmns]

Richard...you said you wished there were other intake manifolds available for the 472-500 Caddy. Actually there are. Before the aftermarket - ie - Edelbrock - had a manifold specifically for the Caddy V8, guys used to adapt intake manifolds designed for the 429-460 Ford. I've never tried it but apparently the width and the port layout of the 429-460 Ford intake manifold is very close to that of the Cadillac and with a bit of machine work can be fairly easily made to fit. Since there are a huge variety of performance manifold designs made for the 429-460 Ford, this opens up a similarly huge number of intake manifold possibilities for the Cadillac. You might want to look into this.

[@richardholdener1727]

thnx-we know about the 460 intakes-its a fair bit of work

[@derekdelsonno874]

Have you done a 455 Oldsmobile yet ? I wish you would

[@richardholdener1727]

have not

[@DannyVillagrana]

How do I keep up horsepower on a corvette

[@3800TURBO]

Its really starting to sound nasty too. Love ya work Richard.

[@wreckanchor]

Is this the engine from the Gremlin?

[@s2upid]

I didn't see a single pair of faded white new balances in this video series. I'm not sure if the carb results can be trusted because of that.

[@genemauguin8611]

To the guy saying the Holley 4010/4011 series are Carter based carbs. They are actually based on Ford 4100 4bbl design. Early models had poor primary annular discharge boosters.

[@juancortez4428]

Are you still running the hi compression heads or low compression heads for all these test?

[@richardholdener1727]

we tested both

[@davelowets]

Pull that Quardrajet on the dyno for 11 or 12 seconds at a time, and see if you can keep the small, single, fuel bowl full. Don't get me wrong, I love a properly tuned Quadrajet on a warmed over street car, but the fuel bowl situation ultimately limits your top horsepower number with it. I've been in the high 10s in the 1320 with a 3500lb car and a Quadrajet, but to try and go much faster with it was a struggle, and I gave up at that point and went with a Holley. 🤷🏻