Ivan: I have a mildly built 292 --(.030 overbore, bigger intake valves, Crane cam, Rhoads lifters, Offy 4-Bbl intake, Clifford headers.) I have the Holley 4160/8007 @ 390 CFM. I've had this same carb for 28 years (incl. 2nd engine). I have a friend who's an old school Holley fan, so he tunes it for me -- I don't dare touch it myself. Right now, I've gone to a later opening power valve [6.5"Hg from 8.5"Hg] and the 50CC accelerator pump. We're still not sure if the baseplate is warped after all this time. A new one is about $130.
I have Carter AFBs on 2 other trucks with V8s, 600 CFM on a 350, and 750 on a 454. Since Edelbrock has taken over marketing of these carbs the price has gone up and the outside finish shinier. Carter used to make a 400 CFM AFB carb, but Edelbrock doesen't sell these, so they must be obsolete. I like the AFB-type because it has no fragile power valve, is less like a swiss watch, and I can rebuild it myself.
If you want the 500 CFM Edelbrock AFB, Jegs,
www.jegs.com has them for less than Summit. $225 for the Edl 1404 500 CFM AFB w/manual choke. $289 for the 8007 Holley 390 4160; other carbs from Jegs' I might consider for my application [which is close to yours] are a Holley 450 CFM chokeless 4Bbl [510-O-9776] for $189, and a Road Demon Jr 4Bbl 525 CFM vac secondary, w/ manual choke for $260.
Running my engine build data on one carburetion website, it came up with 406 CFM as the ideal flow for my set up. But in the old school, they used to beat into our heads, the maxim: "less is more."
