Originally Posted by Glowgeek

Interesting shot of my 82 piston. When I first saw it I thought, Wow detonation and cracks!!! Neither, just post casting shrinkage or some kind of casting flaws that were too low to machine off. Whew! Still, I'm not jumping and up down for joy at how it looks if you know what I mean.

I was very surprised to find that no machining is performed to create the valve reliefs, just cast and left that way.