Someone asked this in the Jeep forum a week ago or so but no one seemed to know any answers there. Here is the question:

What is the most desireable q-jet? What year and what features should I be looking for to get a good rebuilding candidate? I don't need to know any numbers unless they say exactly what features it has. What I'm looking for is manual vs. electric choke, what years, emisisons? Can anyone help?

J. J.

Why dont you start by telling us what motor you want to put this on? :flipoff2:

The most important thing in looking at used Q-jets is the condition of the throttle shaft bores. Grab the primary thottle shaft and wiggle it. If it feels loose, it will need to be repaired. NAPA and some other places sell bushing kits to repair the base plate. For a reasonably built 350 chev. (350 H.P.)I would recomend the '70 to 72 Cadillac 472-500 Q-jet. The jetting seems to be spot on. Any 68 to 76(?) 49 state carb is a good starting point if you want to play with jetting. They are all identical at 780 CFM. If it has wires hanging off of it, throw it away.

HEY Damn it! Leave my Caddy Carbs alone :flipoff2: Hard enough to find those things to put on cadillac's :p

Brook

Originally posted by zags
They are all identical at 780 CFM.

Nope, they're not. If they were the 3.8/4.1 would never run with its stock qjet ;) rare I know... but its out there and it looks identical if its sitting in a bin

I and many Bronco guys are running '69 chevy truck carbs- manual choke.

Turn is backwards and connect the vents- then go whereever you like!

Originally posted by mike
Why dont you start by telling us what motor you want to put this on? :flipoff2:

I didn't think it would matter since people would assume it's going on a V8,but mine is going on a 350. They guy who posted in the Jeep Forum was putting it on an AMC 360.

Anyway, I have an old 1973 Chevy q-jet off a truck 350. There's no wires connecting to it. Is it a good candidate?

J. J.

Originally posted by mike


Nope, they're not. If they were the 3.8/4.1 would never run with its stock qjet ;) rare I know... but its out there and it looks identical if its sitting in a bin

There's also an ~850 cfm model. These can be identified most readily by the booster venturi with a lump and more open appearance. Once you've seen one, or a picture, and know what to look for you can spot them instantly.

I'm also running a '70 Cad carb; there are truckloads of those here, but $50 each. Most in need of primary shaft bushings.

A '73 truck 350 should be ideal, especially since you've already got it and it's going on a 350. Probably won't need jet/rod adjustment at all. It's most likely an old-style (70xxxxx series) without the aneroid cavity. I prefer these for simplicity, others like the newer ones. Can't say that I think there's very much difference.

Use it! :)

edit: I also prefer manual choke, so that simplifies things considerably.

Originally posted by mike


Nope, they're not. If they were the 3.8/4.1 would never run with its stock qjet ;) rare I know... but its out there and it looks identical if its sitting in a bin
Yes, they are. There is also a 850cfm model used in heavy trucks but it is pretty rare. The secondarys are crude variable venturi setup that makes them very versital.