A few years ago, Mopar Muscle Magazine did an article with a 392 HP build on an otherwise stock 340. It was with a Comp Cams XE 268, headers, Edelbrock Air Gap manifold and an Edelbrock 800 CFM carb. I built the same motor, except I used the 750 Edelbrock carb. It runs great. I followed the instructions (and a little common sense) and tuned it pretty well. It'll roast the tires. I'll keep my 750.
Mike