"Can I go a little higher on compression with the alloy heads"
I've always heard that you could go a tad higher without detonation on aluminum heads cause they absorb the heat and get rid of it quicker, where as a iron head will retain the heat.
But still I wouldnt think it would be that much higher than a cast iron head though.
About 10.5 to 1 or 11-1 is as high as you want to go with pump gas, no matter what head your using.
Cp