We have been around the block once or twice
However, I cannot come up with the numbers you are coming up with
If I use a .040 gasket, .006 deck, and no valve relieve at all, with 74 cc (all guesses), I get 11.74 ...
.not that you can run it that way, but certainly tighter than what you reportedIf I use a .060 gasket, 4.40 gasket bore, (realistic for a .006 proud piston), a 74 cc chamber, and 5 cc of valve relief (which seems low for a Racetech), .006 proud deck, I get
10.59. CORRECTED
If you could provide a picture of the label on the Racetecs to show exactly the compression height and valve relief, we can see if makes sense.
ON EDIT: The reason for my last comment is that it is very difficult to measure deck clearance without a dual dial deck bridge. Often even being careful with a single you can induce rock. I like to do it with the degree wheel on, with TDC found with a piston stop and a dual dial to take all possibility of rock out of it