If you can supply a stock 350/355 or one that needs rebuilt, u can take it re bearing it etc/ for 600-800, get a victor Jr Intake ~270 and at the least World Product Sportsman II Angle plug heads (520 ea). than of course .480-.520 cam w/ lifters 230-340

Or a quick fix buy the crate motor and put like a .540 Lift cam in it