I really like the parts selection you put together, i'd run it myself...........But, if a stock block 72' 318 made that much compression with 63.0cc heads it would be a true gift from Ma Mopar. Stock pistons are just too deep in the hole for those numbers. 8.3/8.5 would be more realistic in my opinion. If it was a true 9.2 to 1, you "could" run a little more aggresive cam if your looking for some extra power upstairs.
P.S. To be fair, i did allow for a little eyebrow volume. If it has true flattops, the numbers i posted above could be a hair low on this application.