Update - When we ordered pistons we were shooting for 12.5:1 but I'm only getting about 11.5:1 and we think the problem could be that valve relief number they provided on the piston card, pretty hard to believe that there is a -13cc in just the valve relief. We were expecting 3 to 4 so that would cause me to loose a point of compression so I'm going to cc the pistons later today.
Back in 2014 when I had custom Diamond pistons for my 440-1 engine with 4.500" bore, the valve relief's were 8.2cc (Diamond's number). And my valve reliefs were smaller and not as deep as yours. I was expecting about 6cc, but that is what the sheet said.
Intake: 0.290" depth, 2.3" dia relief
Exh: 0.265" depth, 1.84" dia relief
