I considered the ProComp heads when I started putting my 331 together, but did some on line research and one comment that convinced me to not buy them was "the only thing they are good for is if you want to say you have aluminum heads on your car." I spent a few bucks extra and went with Edelbrock Performer RPM heads, and feel they were worth the extra.

I agree that a good set of iron heads in the price range you are talking about might be a better choice.

Don