273 302 318 340 build
So more info on #2 318
Measured 3 holes. Average depth in hole was .0470" below deck.
Believe these are TRW pistons for 67-70 318. Advertised compression is 9.2 when used with 69cc heads and .039 thick gasket.
The guy sounds helpful/knowledgeable I hope to get a look at it this week.