Interesting threads there! All I did to my Pro Comp 210's was clean up the runners and gasket match them to my intake and headers (I punched out the header gaskets to match up to my Hooker Super Comps and then matched the exhaust runners to the gaskets). Just the gasket matching opened them up considerably. Other than that, I just lightly cleaned up the chambers. The pushrod holes seem fine, and the machine shop that assembled them with my valve springs said everything looks fine. I guess we'll see very soon! My 424W is completely assembled and waiting to get on the dyno hopefully next week after the holiday!