What was the c.f.m. rating on a 1979 quadrajet carburator for L -82 Motor? What is a good replacement for stock L-82?
Most replacements I've seen in catalogs are 795 cfm, and this seems high to me. What do you think?
Ken

I believe the stock Q-jet is 795 cfm for an L82. It does seem like a lot for a small block, but remember the ratings are what the carb is capable of flowing and the Q-jet has small primaries.

Several months ago I considered replacing my Q-jet on my '78 L82. I checked with Edelbrock for what they would recommend, and they said their 600 cfm carburetor would provide crisper throttle response. I checked into a direct bolt-on Holley rated at 650 cfm, and it wouldn't fit without re-locating the EGR valve. I ended up having my Quadrajet rebuilt by someone who knows how and haven't been sorry at all. The money I saved by having the carb rebuilt instead of replaced I put into an Edelbrock Performer intake and the car really runs great.

Q-jets came in two sizes, 750cfm and 800(795)cfm. The difference is in the primary bores, there is a noticible reduction in the smaller one. The reason this same carb worked on everyghing from the 250cu-in pontiac ohc six to the 500cu-in caddys is the small primaries combined with the secondary air door that only gives the motor as much air as it can take. Joe

Some of the Q-Jets were as small as 500 cfm. Never on a Vette. These were used on some V-6 engines.
I always rebuild the carb rather than replace it. A good rebuild will work very well. Many folks don't rebuild them properly. Over 30 years, I have rebuilt a few hundred carbs. Personally I prefer the Q-Jet to any other carb for street use, and fairly stock engines for racing. It's a good carb, properly done.
600 or 350 is good for many street applications, unless you added some go fast goodies. Many Vettes have these right out of the factory, and use larger carbs.

Some of the Q-Jets were as small as 500 cfm. Never on a Vette. These were used on some V-6 engines.
I always rebuild the carb rather than replace it. A good rebuild will work very well. Many folks don't rebuild them properly. Over 30 years, I have rebuilt a few hundred carbs. Personally I prefer the Q-Jet to any other carb for street use, and fairly stock engines for racing. It's a good carb, properly done.
600 or 650 is good for many street applications, unless you added some go fast goodies. Many Vettes have these right out of the factory, and use larger carbs.

Forgive my typo in my first post, 650 not 350.

Ken Styer

If your keepin that L-82 stock then I think the stock Rochester Q-jet is the thing to have. True a 350 doesnt require more than about 600 cfm but that's at top rev. The edelbrocks I've had have run smooth and great but they suck down alot of fuel under normal street conditions, the Rochester on a stock L-82 will give you the best all around performance and mileage.

I've been reading quite a lot about quadrajets lately, as I'm trying to learn how to work on mine. From what I've read, a 350 only flows just over 600 cfm at 6000 rpm. But, this is at 100% volumetric efficiency (VE). Most production engines only have about 80-85% VE. So, a normal street 350 will only flow 500 cfm or so, and that's only when you get up around 6000 rpm. Unless you have a super high performance 350, or it's bored over, a 600 cfm carb is plenty. The Quadrajets were designed to be capable of flowing up to 795 cfm, but were set by the factory to deliver precisely what that specific engine needs. The secondary throttle valves are set so they only open far enough to allow up to 590 cfm or so. The quadrajet is fine for your car, as long as it's set right.