As with all the Pro Comp castings, they are from a Chinese foundry...hard telling who's head they copied... I have seen some problems with the porosity of the Chinese castings, along with some poor fit of the ports, etc. I guess it's a matter of how lucky you feel, maybe you get a good set, maybe you don't... I doubt there is very little, if any quality control on the castings themselves....so do the parts inside make up for that???? Don't know, that's your decision. If price is the only consideration on your choice of aluminum heads, they'll probably be fine.... Think I'll stick with the US made castings, myself....