I've had two pair of those heads(all eight chambers on both sets) that I CC to use years ago, they where all above 80.0 , some as high as 84.0 CC
if your trying to use that 1966 short block I would check the deck heights as already suggested and go from there.
I'm thinking the smaller close chamber heads would be my choice if those pistons are at least -.020 or more in the cylinders