How far in the hole 318 pistons
They would have to be either down, dished, or some combination, and IIRC, they were at least dished.
and
none of the five early ones that I have were much out of the holes, at least not nearly .045..... In other words, they may not have been 10.5 engines. More like 10.0 with the thin steel gaskets, and as low as 9.5 with the FelPro .039s