If it really was that high in the hole, then you would indeed be up in that SCR range with 675 type heads. I have not ever heard of a stock piston at that height in the bore. Very interesting, and thanks for the data point; I'll see if I can find anything else that supports that. (I won't just run with the FSM CR numbers however... they have proved to be 'optimistic' over and over...)
For sure, it was/is an LA and not a Poly?