The 327 piston would be about the same compression? Not at .125 over.the compression would or should be a little higher then that of a .030 bore and the 307. With the standard 250 head you should be closer to a 10-1, over the like about 9.5-1 with the 307 and .030 bore.

Larry/Twisted6
[oooooo] smile
Adding CFM adds boost smile
shocked God doesn't like ugly.