Correct and very perceptive, sir. They were special TRW domed pistons designed with a 'quench dome' on the spark plug side that came up very close to the stock chamber wall on that side, and a slot in the dome for the flame front to pass through. One of the claims made was that the quench air 'squirt' would push the flame front out faster and help the combustion process. The designed CR was over 11, but I ground out the other side of the chambers some to get the CR down to the low 10's for pump gas, and CC'd them all. I dunno how good the quench was, but the engine ran without detonation on pump gas, and the DCR had to be up in the mid 8 range with that cam. (60 degree ABDC intake closure).