Denny is right, you will never be happy with a 305 (at least I wasn't, literally the worst motor I ever had), a 350 or even a 383 and the family of gen 1 small blocks are all physically the same size, opt to get another ci small block, that 305 was a smogger motor and couldn't pull its own weight. Be patient also, my buddy just sold a 383 out of a show car with 4k miles on it, edelbrock aluminum heads, quick fuel carb and complete carb to pan for 800 bucks, the deals are out there all the time on small blocks, or even like Denny mentioned a crate motor. Just my two cents, having fun is what its all about and a nice car with a poor motor wouldnt be fun, at least not for me. those are cool cars but didnt have good motors, make it cooler!