[luckynumberslevin]

Hey guys, i finally got my truck together ready to drive and im missing a carb. I have a 74 Q-jet that needs a rebuild that i could use but ive been told its hard to find kits for them and not really worth while rebuilding. Its gonna be a cruser with some track action. Im on a tighter budget but open to ideas.

[Ron Golden]

The Q-jet will work well. Rebuild kits should be available at any parts house.

Ron

[sirron]

The q-jet is a good match, very rebuildable carb for the 283. There is a place in Alberta that can probably be able to fix you up.The Carburetor Doctor. I hope this link will work for you. Good luck with your truck.

http://www.google.com/url?sa=t&sourc...6W9lpTR4ezFyvA

[luckynumberslevin]

the rebuild kits i see on summits site, made by jet and edelbrock... are they compatable with my carb or only jet brand q-jets?

[DoubleVision]

All the carbs that jet carries is a rebuilt Quadrajet. If you`ve never built one before I recommend you let a company with a good rep do it for you. There are some companies out there such as summit that have rebuilt Q-jets ready to bolt on if you`d rather take that route. Check the condition of your Q-jet to make sure it`s worth rebuilding. Worn primary throttle shaft is one thing to check and I`m sure there`s web sites out there that will give you all the things to check. Don`t believe anyone that bad mouth`s a Quadrajet, they are just showing that something simple as a Carb confuses them as the
Q-jet is one of the best carbs ever made especially for the street.

[willowbilly3]

Quadrajets came in a wide range of cfm ratings. It might be good to know what size you are using. 500 cfm or less for a 283 unless you are really twisting it.

[cobalt327]

Originally Posted by luckynumberslevin

Hey guys, i finally got my truck together ready to drive and im missing a carb. I have a 74 Q-jet that needs a rebuild that i could use but ive been told its hard to find kits for them and not really worth while rebuilding. Its gonna be a cruser with some track action. Im on a tighter budget but open to ideas.

While a Q-jet would be a great choice for your 283, you need to determine if it will work for the application. An example is if it has the correct linkage to hook the detent cable to, if you are running a TH350.

The original application can be partially determined by checking the stamped in carb number from the driver side by the secondary linkage. The number will be something like "7044240". Take the number to Cliffs and see what you have and go from there. Cliff has a forum if you want to ask him or the board there a question, but I believe we here at Hotrodders can answer most of the questions you may have, too.

There are some tricks involved w/dis- and reassembling the carb, but nothing you cannot handle, I'd bet. There's a detailed thread HERE that may help, and many other threads on Q-jets in general if you do a serach.

Q-Jet Parts Galore- Gessler.

Q-jet rebuild w/photos- HERE.

Q-jet Carb Adjustments- HERE.

Manual- HERE.


Good luck.

[curtis73]

Originally Posted by willowbilly3

Quadrajets came in a wide range of cfm ratings. It might be good to know what size you are using. 500 cfm or less for a 283 unless you are really twisting it.

Not quite correct... Qjets only came in 750 and 800 CFM. The nice thing about a Qjet is the vacuum operated secondary doors that only flow what the engine needs. GM used Qjets as late as 1991 on everything from V6s to Caddy 500s, so they'll work on a very wide range of engines.

[cobalt327]

↑X2

Kind of counterintuitive, the large 800 cfm casting Q-jet was used on truck 4.3L V6 engines all the way through '86. Adjustments to the air/fuel calibrations, to the secondary throttle linkage and to the unloader(s) and air valve can compensate for a wide range of applications.

For those interested in minutia, there was another carb used on the '71 HO Pontiac 455 that flowed a little more than 800 cfm. It used the same basic 800 cfm body casting, the difference was that the outermost booster ring was deleted. No changes were made to the venturi or throttle bore diameters. But these carbs are so rare, they might as well be made of unobtainium. The value of a verifiable carb like this could finance a decent SBC engine build.

[frodin1]

If you go to Summit, and look at any of their carbs, there's a CFM calculator on the bottom of the page. Just type in your Cubic inches and max RPMS, and it'll tell you what to run. I've found it to be pretty accurate to what others have told me.

[Hippie]

I had good luck with the Summit Q-Jets.

[DoubleVision]

I`ve explained to a few in my time that a Quadrajet is a air dam carb, it only flows what the engine demands and I get looks like I`m speaking another language. As long as the jetting and the secondary butterflies are set correctly with the tension adjustment, it could be a 1000 cfm and it wouldn`t make any difference as it`s only going to give what the engine demands.
I`ve played with Holley`s and I don`t like them mostly because they are rather cheaply made. Everytime I`ve gotten a new one to set on anothers engine there`s always parts missing on it. I don`t like Edelbrock carbs as the rear fuel inlet means a mile of fuel line directly over the engine and heat rises. The "shave" secondary adjustment means you have to get it right the first time. Then if you want to move the carb to a different engine you have to find a way to add weight to the secondarys to set them correctly for the demands of a different engine if need be. Why I like Quadrajets as the small primaries make for almost fuel injection type sensitivity plus good for fuel economy. When maximum flow is needed you floor it and the huge secondarys give all the engine demands.
Back before I got into carbs I used to run holleys and was okay with them as they were very easy to work on, Within a year the secondary shaft bushings were worn completely out and they didn`t make replacements for them. When I found they were 2 cent plastic pieces I got rid of it and forced myself to sit down and learn a Quadrajet, when I found they work almost the same as any other carb I found them easy. Quadrajets look complicated but they`re not. Some guys cuss them and call them all kinds of names but any carb that don`t run correctly no matter who it is they`re gonna cuss and call it names, the Quadrajet just happened to be the one that carried the rap since it`s complicated looks was too much for them to figure out.
THe best part is when you hit the drag strip running for fun against other street cars and you bust them they`re shocked when you open the hood and they see a Quadrajet on it then they`re asking you how you got it to work on a hot rod.

[ap72]

Holleys are much more tunable. Any carb can work well if handled properly though, it all comes down to preference, its like ford vs chevy.

[cobalt327]

I know of no parameter of a Q-jet that can't be modified that can be on a Holley. Maybe easier to tune, but sure not "much more tunable".

[454C10]

I prefer a q-jet but if it doesn't work out.

use this Holley and adaptor plate if you have a spread bore intake.

http://www.summitracing.com/parts/HLY-0-80570/?rtype=10

http://www.summitracing.com/parts/MRG-1932/