Originally Posted by my87Z
Second question is there a design fault in the factor piston? by the calculations i have the quench would be about .065 which within the optimal range of .06-.08 correct me if im wrong.
I think what he is saying is that only flat top and D-dish pistons will provide the best/adequate quench. They are flat on top where they fit directly underneath the flat part of the head (ie not the combustion chamber). I think the rule of thumb is that 1/3 of the piston should provide quenching action (or maybe its 2/3, I forgot).
A dished piston will have a little rim around the outer edge of the piston. The little rim is not enough surface area to cause a violent squishing action of the charge over into the combustion chamber area. Nor is is a large enough surface to help transfer heat from the piston to the cooler head.
Deck clearance and squish are not always a direct relationship.