All Factory Best Bang??

383 .030 over with a 4.15 inch crank for 478 cubic inches (.040 over makes right at 480) or 400 with 4-3/8 bore and 3.92 inch crank for a tick over 470. Big Chevy aluminum rods are pretty much standard here, and it’s also advisable to use aluminum main caps with studs. Detonation is a matter of “when“ instead of “if” your limited to iron heads and pump gas when your almost stalling it out from WOT at full rpm. Old 915 1967 closed chamber heads with the close to 906 head ports might would be okay, but optimal (if you could get by with it) would be some iron INDY heads.
Here’s a little food for thought I had read some time ago. Not that you could pattern your build exactly like it, but still informative enough to give some ideas.
https://www.hotrod.com/articles/dodge-pulling-truck-chrysler-400-engine-build/