So my assumption that a steel crank engine in a 72 was a leftover 71 is incorrect so these 72 engines were built to 72 specs, I.E. dished pistons and not leftover engines built to 71 specs, I.E. flat tops. Pistons are cheap enough in the grand scheme of things I was just trying to cheap out and get extra blacks in the process. I think the NHRA guidelines help in the conversation from the simple fact that they show a significantly shorter piston which is based on a significantly short factory version of the piston.

Thanks for all the input folks.