I looked up the piston, KB745.
It is for a small block stroker engine (408").
The compression height is 1.465" to the top of the piston, not including the dome part.
The piston is step/dished with an effective dish volume of 20.5cc.
There is no description of the step / quench dome height? You may have to call and ask?
I would estimate the quench dome is about 0.050" and maybe covers 1/4 of the piston? Volume of 4.00" bore and 0.050" depth = 10.298 cc. Assuming the Quench done is about 1/4 the piston top that would be about 2.6 cc (rough estimate) if the quench dome was milled off.
This would make the dish close to 23.1 cc.

Assuming this is for a 0.030" over 360 (4.030" bore) stroked with a 4.00" crank, and assuming the dish volume is 23.1 cc, with a 0.040" head gasket (about 9cc volume) then the compression ratios would look like this:
64 cc head = 9.48:1 compression
68 cc head = 9.14:1
72 cc head = 8.84:1

Note: this assumes a -0.012" deck height.