Is this a Boss 429 piston?
I was at an old machine shop this week, and there's always broken stuff on display. I see this piston/rod on top of a 6' diesel crank, when it hits me it's a 385 rod/piston, the old TRW "8" piston skirt too. I notice it has a Ford part number on the piston, a C9 rod. I ask the guy what it's from, he thought some truck motor from the early 70's. The valve is sticking through the top of the piston, and there's not really any damage, it broke, turned and got stuck in it! I told him I thought it was a Boss 429, but he wasn't sure, he got it from an old rebuilder from the old days, Shaw Brothers. It was a fresh build that went wrong.