With the 4.125 stroke and a flat top at zero deck, compression is a little higher than I would want for pump gas using an RPM heads normal chambers.
I took mine out from 63.5 to 68 cc.
It worked out well with the way I wanted to shape the chambers.
And Dave, I like the 4.125 stroke over the 4.00 inch mainly for the lighter putting. The extra stroke causes no issues with skirt and bore wear if its built correctly.
And the torque can be pretty nice!
Keith