aluminum heads

The Pro Comps are just like the Source heads, but not as well thought out. I have yet to see anyone who has them post how great they are. Whether or not I agre with the results at least Source has/had that.
As for the OP - Edelbrocks are still the best bang for the buck in aluminum. No aftermarket head is good "out of the box". WHich is why many now are available bare. Expect to have a shop check and correct them. Usually it's guide clearances and replacement of valve springs. In my case(s), I have the valve job redone and I have them milled to set the chamber size more than due to defect, but the valve jobs are pretty bad from the manufacturers. Normally, RPMs with this type of prep are about $700 more than a similarly rebuilt performance set of iron heads with no porting, and will flow aroun 240-245 which is slightly more than the typical X/J/915/596/308. I'd much prefer to run aluminum if the budget allows, but not all do.