K4KAK

I have a 1990 camaro rs. 5 speed. The engine is a non-computerized carburated 305. It has no power for a carmaro at all for a straight shift V8. I ran the carb number thru the internet and it comes back to a 1978 3.8L Turbo V6 Buick. The carb needs rebuilding... The idle air screws just wobble in the hole. You can wind one of them all the way in and it wont kill the engine or you can take it completly out and the engine wont die. You would never know it was a 4bbl carb. It's a Quadrajet and they moan loudly when opened up but this one doesnt do any thing....Secondly, how can I tell what kind of intake I have? Is there a number I need to look for? A marking of some sort? This v6 carb is throwing me off....It may be just fine but I cant believe it would be. For now tho, I just want it to run smooth.. It misses and shakes, not enough power for 5th gear until you hit about 70mph

blue birdy 87

I'm no expert, but that should be way to small of a carb for that motor. Its very possible that the carb is what holding you back, making you feel like you have no power.

Instead of rebuilding it look into putting a proper sized one on the car, you should not have that problem at 70.

KrisW

iTrader: (5)

You might just find that the turbo Buick engine had more power than that 305.

At any rate, when you rebuild that carb, you just need to calibrate it for the horsepower you intend to make. If it's used then it's as good as most any late 70's quadrajet.

You also might be able to sell it on ebay or the turbo Buick forums to a guy restoring his hot air Buick mill.

Chevy8588

iTrader: (1)

you also have to watch out for old q jets, they tend to warp the top plate which opens up an internal air bleed. basically a vacuum leak in the carb

K4KAK

Blue Birdy 87 I think your right but I'm no expert in any way. I think the CFM on this carb is around 400, but again not an expert. I think my car requires a 650 to 750 cfm.. Thanks for your reply

K4KAK

KrisW, I really dont know what kind of horsepower it is capable of. Its a piece together rebuilt engine... This what I know, the previous owner said 305HO, vortex heads, short tube headers and thats about it. Good or bad I have no idea, but thanks for the reply....

K4KAK

Chevy8588 I will keep that in mind, I'm going to rebuild it because I dont have any other at the time. I will check the flatness of each piece... The air adjustment screws just woble in the hole, I dont think there suppose to do that... thanks for the reply.....

mmadden55

Go to Craigslist and get a Rochester off a 2nd gen 350. Or get a 600 to 735 Holley. I have a 2nd gen Rochester off a 350 on my 86 runs great!

K4KAK

Here is some information on the carb on my 1990 Camaro....It is a 1978 Quadrajet from 3.8L Turbo Buick....

First row of numbers say 17058240...Production
Second row of numbers say 3467 BLS...
Body A,B
Service 17055841
4M4ME

novaderrik

every quadrajet ever factory installed on anything was either rated at 750 or 800 cfm- this covers everything from the 120hp 4.1 Buick V6 up to 500ci Caddies- and Edelbrock used to sell an 850 cfm version. it is such a versatile carb because the tiny little primaries only flow a couple of hundred cfm for crisp throttle response and good atomization of fuel, and the big doors on top of the secondaries only open up enough to give the engine however much more air and fuel as the engine wants at any given time.

the lack of power sounds to me like the secondaries aren't functioning for some reason- check to make sure the lever on the choke housing flips away from the lever on the secondaries to allow them to open when the choke opens and that the air door on top of the carb moves freely. the lack of working idle mixture screws either means that you don't have enough initial timing (i have ove2r 45 degrees with the vacuum advance hooked up at idle) and have the throttle blades open too far at idle which exposes the transition circuit. or the carb is all gummed up and needs to be taken apart, cleaned, adjusted, and put back together with a quality rebuild kit and a new float.

one quick and easy thing you can do is take each idle mixture screw out and shoot some carb cleaner in each hole to dissolve any accumulated gunk.. while you are in there, hold the choke open and clean out under it with the carb cleaner to clean out any holes that are in there..

K4KAK

thanks guys all good information.

William Scott

The factory fourbarl is quadrajet 4m4me I have a 87 Camaro and it has the same factory carb on it the same as yours call's for

William Scott

A Holly 600 cfm will work just fine to

NoEmissions84TA

iTrader: (1)

Check the posting date......... 5 years ago.

mmadden55

I find the easiest way to fix this problem is with an aftermarket manifold and carb, edelbrock performer or air gap and holley 600 to 750 cfm carb or a summit carb. New or off craigslist if money is an issue. /And yeah I know it is an old thread.