I think you have your answer, stick with the exhaust and mild improvements. I once purchased a 305 (only because I wanted the tranny bolted to it.) The young man I bought it from put a Performer 650, Edelbrock Torker II intake, headers, some radical cam, New HEI dist and all with stock bore and 2 bbl heads. It sounded good at a idle but would fall on its face. Hmmmm!
