If it's original matching engine, I'd get a 400 to build and preserve the original 383. 50 year old stuff breaks and you can't replace it, the 383's have the weakest of the big block main webs; the 400's the strongest. A 400 core should be in the $250 range.
A 451/470 stroker engine with 440 source heads could be well over 500HP and look like a stock motor. But you're looking north of $5K. S/F....Ken M
