Since the al heads suck so much heat out of the chambers, installing them is like dropping the compression between .5 and 1.0, so I have concluded.And it does this at the worst possible time; anytime the engine is not at WOT.
So if you really want them,and you do a lot of non-WOT driving, they willwork best with a compression increase. Then that leads to Dcr theory, and squish/quench.
