How low of c/r do you want to go? The 514 with about 9.0 to 1 can produce 560-600 hp depending on the overall combo. Are you planning on aluminum heads? What carb/manifold setup do you want? what about exhaust, manifolds or headers? I've seen 10 to 1 514" Fords making 760+ HP but these are usually up scale engines with good heads[with work], roller cams and big carbs and top of the line parts. It all depends on how far you and your wallet want to go.