I'd be looking for gains with the shape of the piston top, flame travel and all that witchcraft. It's safe to assume the new heads flow a bunch more than the old ones?

With that displacement there should be no shortage of NA torque so I'd keep the CR in the 7's if I could and if 8 psi didn't make me smile there's always 10. I think the lower CR gives you that possibility on gas.

Kevin