Brainstormin' 440 vs 5.9 ...

Likely from tuning mistakes. Cast pistons can take a beating, they just can’t take detonation.

I guess I shouldn't mention the 440's were pulled out of trucks/MH's and other assorted land yacht and smacked them with a 250 shot. Detonation is indeed the killer. They can take a beating. If they blew up, off to the yard for a fresh one and hope the good valvetrain wasn't hurt!

8:1 bone stock short block with a 557 solid, some got rollers, ported iron heads and .

They ran OK and made us a bunch of money.

I think you are going to be weezing for RPM/power about the 1000' mark with the 440 with that gearing. That is where that magnum 360 will be better off at the 5500 mark.