400 stroker build....for a boat

The common 512 combo uses a 1.320 CH piston, same as the common 451 combo. The common 470 combo uses a 1.480 CH. Of those two choices, I'd prefer the 470. More cubes is almost always better.
I work with a lot of sub 1.100CH pistons in NA motors, albeit mostly small blocks and they live fine. Power adders are where you start seeing issues.

What are you planning to use for fuel? Are you doing port injection or something like the Holley/FItech throttle body injection? S/F....Ken M