if I had to have 500hp from a 383 i'd pro-charge it. 500hp from a 383 with big cams, FI, big crank, big heads, etc just sounds miserable to me. a real 360hp-380hp for a pump gas driver would be fun; done this before. a warmed up pump gas/license plate, reliable, easy maintenance 400-420hp 431 would be more fun. blowing a bunch of money for the more exotic build and just plain enjoyable fun aren't always on the same page. low gears and loose torque converters are miserable. another thing; can you tune the more radical build? how dip can the money pit be dug before you begin to regret it?