I took physical measurements this morning and triple checked them:
BORE: 4.030
STROKE: 3.48
GASKET: 4.135 X 0.040
ACTUAL CHAMBER: 63.0cc
PISTON IN BORE: -0.3cc

SWEPT VOLUME (4.030)(4.030)(3.48)(PI/4)(16.387)=727.4cc
GASKET VOLUME (4.135)(4.135)(0.040)(0.7854)(16.387)=8.80cc
NET CHAMBER 63.0+8.80-0.3=71.5cc

SCR (727.4+71.5)/71.5=11.17

INTAKE CLOSED ON SEAT @65*ABDC MEASURED STROKE LEFT=2.697"

THIS WOULD CHANGE THE ABOVE SCR TO 8.88 FOR A MEASURED DCR.
IS THIS PRACTICAL FOR 89 OCTANE OR BETTER?

I still do not know why the two sets of heads under the same casting #'s and with no previous machining came up different, but I have them in my hands and know it is so. Now what can I do with what I have? I was thinking of putting the 76ers together but I dont like the numbers much. I could have the 64's machined for 2.02/1.6 valves with an unshroud sweep. this would open up the net chamber some but would it be enough? An additional 3.5cc would bring the DCR down to 8.516. Any thoughts?