Dust off your crystal ball and GUESS the horsepower !

You wouldn't mill the 360 heads a little to keep stock cr ?
I would mill them at least enough to compensate for the thicker Fel Pro head gaskets. The goal would be for the engine to run fine on 87 octane ethanol infused gasoline.
An iron headed 318 should be able to handle 8 3/4 to 9 to 1 compression on 87.