Originally Posted by rickseeman
Originally Posted by 68jim
I did not build this engine and assumed they were Keith Black Hypereutectic pistons.
68jim

I would never assume that. I don't even know if those existed back then. My guess is that is an old TRW forging number. And could very well be 12.5 since that was a common race cr. If you take the spark plugs out and look inside 12.5's come way up there.



Agreed, a 12.5 piston ( shown ) will have a sharp dome on it compared to say a 10.5 piston

Hemi-Dome-Pistons_426+hemi+pistons.jpg