Looking for Info / Specs on Obsolete Mopar Piston

That's correct, the 11.5 to 1 compression ratio with these pistons is calculated/assumed with the flat part of the piston .019" above deck, which puts the dome right up there against the combustion chamber, necessitating the substantial valve notches. But the notches in the other TRW "obsolete" 12.5 to 1 pistons are even bigger!