Several years ago a bunch of Eagle 4" cast cranks broke, IIRC most broke right behind the #1 main cap or in front of the #5 main cap. Several of them were in mild builds that weren't beat on hard.
Ramm said on this motor, “was the result of many things ending in catastrophe. ”.
I’d think many of the other failures were similar too: assembly, machining, parts combination, other parts quality, environment (slicks, converter, line lock), tuning, etc.... And some just assuming too high limitations for HP.
It’s harder to play detective when many contributing factors. Especially over the internet.