65 cc chambers (63 cc chamber Edelbrocks with the valve area worked and adding 2 cc's, NOT the 65 cc Edelbrock with the open chamber design)
Add 1 cc or so for volume down to the top ring
then SCR is 11.5
With the 312 solid cam installed with the intake centerline at 108 degrees, then DCR comes out to 8.1. Note that the DCR computation is dependent to some degree to the valve lash and the effective angle at which the valve closes, so ' in the low 8's ' is the better answer. But low 8's for AL heads and an effective quench gap should be quite tunable to run without detonation on pump fuel. You can't be lazy or ignorant on the tuning.