Which heads?

In My post I was trying to make a ref to the power gains being similar. The cubes and combo are completely different.

We have no one showing proof positive here that more compression makes more power but it has been done but not to the tune of more air flow. I'm not sure or sold on the 308 being a better way to go about this. Since from what I gather, the Op has both heads on hand, try them both out!