[blykins]

They're cheap for a reason.

I used a set on a 383 SBC that the customer brought me to use. The valve cover holes were drilled off place and they didn't flow any more than a factory head.

My advice is that if you're insistent on using them, buy them bare and then have a competent machine shop go through them, make sure everything is kosher, then assemble them with quality parts. However, by the time you go through all of that, you could probably snag a good set of heads for the same price or a few dollars more.

The Procomp brand is basically just cheap Chinese knockoffs. Their distributors fail on the dyno, their rocker arms seize up and spit bearings out, their intakes have leaks, etc, etc.