Is the 383 a better engine, or does the 440 just have more displacement?
Since this is big block a-body tech, I'm gonna make an observation, NOT related to which is better, a 383 or 440.
If it wasn't in there originally, I wouldn't bother swapping in a 383, when a 360 stroked 408 (or bigger) is easier and fits much better.
I'm not so sure I would bother with a 440 either. Even bigger and harder to fit.
I WOULD do a 400 stroker, If going fast in a straight line is a priority. 500+inches makes the swap worthwhile.
My worthless opinion only.