Quadrajet Question

[NuBomb]

I am wanting to buy a solid carburator to have rebuilt locally. What numbers should I be looking for. I have a service manual that has the numbers that were used, but I'd like to know if there are some other numbers/years that would be better. I am not posting a WTB, I am just wanted to make sure of what numbers I can or cannot use. Thanks.

[ChevLoRay]

The numbering system for the bodies (I believe) help to tell you what model carburetor it is....or was. Seems that all of the Q-Jets from the mid-sixties and up thru '69, had a seven-digit number that began with 702XXXX. I believe in '70, the first three digits were 703XXXX. Beyond that, you had to look at the remaining four digits to know which engine it was installed on.

Are you trying to restore your engine, or are you just looking for a period-correct carb to modify to your liking? There should be a list of info that you can use to decipher any Q-Jet you find. The down side to looking for a particular carb is that you may be looking for a needle in a haystack.

I just bought a new Edelbrock Q-Jet and never looked back. It may be that by the time you find/buy a specific carb and have it rebuilt, you could have a new one for less.

[dan42]

I have a quadrajet, I think it's around 1980 from the codes, and it's supposed to be one of the better years - the later ones have smog stuff that doesn't allow you to change settings. However, even though it was rebuilt, it starts hard when it's cold (and I'm talking California cold - it probably wouldn't start in the midwest).

[passthebuck]

The best years of Q-jet were the late 70's/early 80's. You want one that doesn’t have an electrical plug going to the body of the carb (wires going to solenoids & the choke housing are ok). You can be sure that you will need to have it rebuilt & new bushings installed in the bottom plate. My Q-Jet had all of that done & after 2 adjustments, it starts just fine at -40. I believe the full-size wagons had the highest rated CFM. I seem to remember that there was a post here about how to tell the difference. I think you had to look down the primary venturies & see if the had a flat spot on one side... ChevLoRay is right though, a new carb has all the good stuff & is ready to go.

[NuBomb]

I've got a carter AFB on it now, and the choke is loading up when I let it warm-up in the morinings. It was fouling plugs pretty quickly. I took it to my mechanic and he adjusted the choke and cleaned the plugs. It is running better now, but I'd like to put a quadrajet on it so I can have the correct choke set up. I'm not looking for a performance carb, just a reliable set up that I can count on. My blazer is my daily driver until another projet gets done. The blazer took 7 years, so that will probably be a while.

[Sport/Truck]

http://www.smicarburetor.com/product...2/productID/47

s/t

[bartstoy]

I went from the original Q-Jet to a Carter AFB. The Carter was acting up after a few years so I just put in a new Edelbrock Q-Jet. Like Chev-Lo-Ray I ain't looking back. Starts right up, and gets going. What is most interesting is if you really look at the Carter and the Edelbrock side by side, and inside to inside, they are almost identical. Just an observation

[Skirkpat]

If your Q-Jet wont start at 40 degrees, it is not a bad carb, it's the tune in my opinion.

[Wrenchbender Ret]

I agree with Buck. Late 70's early 80's. with the round choke. If it is not electric you can put the electric coil in it. Then the choke does not have to be compatible with the manifold. Thats all I run on my trucks. I buy them at swap meets for $5-10. Rebuild them myself & usually dont have over $50 in one.

[texanidiot25]

I can start mine in the 30s with the choke. Though my carb was missing most the choke bits so we had to adda manual choke cable and midify the linkage some.

Besides the dirt coming in from my fuel line, it's a great carb. Fuel efficient in the city with 4.10 gears.

[ChevLoRay]

My truck originally had a Q-Jet on it, but the P.O. removed it and installed an Edelbrock 1405. It ran rich, had a manual choke and gas-fouled spark plugs like crazy. Also, he (the P.O.) had installed it with an adapter, so the setup just wasn't worth a crap.

I bought a new Performer intake and the 1901 Q-Jet from Edelbrock. It has a divorced choke and the electric connection is to open up the choke after the engine is warmed sufficiently.

In my opinion, the Q-Jets that came out prior to the '72 and up engines would be the best performance candidates. When the first Arab oil embargo was upon us, automotive manufacturers scrambled to make the existing carbs as fuel-efficient as possible. It was at that time the the tuning parameters changed, carbs were set to run lean and engines were prone to run-on, after shutting off the ignition. That's when we got solenoids added to forcibly close the throttle valves and accelerator pumps eventually became electronic, hence the nickname Mod-Quad. I would have no use for anything any newer than '71, myself. You do what you want.

[NuBomb]

Great information guys. One of the mechanics at the shop I use is supposed to be really good with quadrajets. I have always heard that a well tuned quadrajet will work great. The secret seems to be someone who really knows what they are doing. I trust the mechanics I use, and I'm going to go with what they recommend.