I don't worry about CFM formulas and such. Throw a quadrajet on there and you'll be happy no matter what your driving style. I know of people with quadrajets on buick 231 V6 pigs, and people with the same (albeit modified) quadrajet on 650 HP 455 oldsmobiles. They'll do it all, you just need to make sure with the high performance stuff, that you keep teh float bowl full. On a 307, a q-jet is perfect. I have one on my (oldsmobile) 307, and with the computer controlled everything, that 800CFM qjet gives me 25 MPG on the highway. For the past 2 months, I haven't seen below 15 MPG. Buddy of mine had an olds 307 with a non-computerized qjet in a 73 omega for a while. with 2.41 rear gears and a TH350 tranny, he got 30 MPG!!! You can't beat quadrajets. Besides, they're cheap and availible in nearly any pre-1980 GM car, truck, van, whatever in nearly any junkyard in the world.
