Casting problems occurred in the second run on these heads. In-proper heat treating but has long been taken care of. A Friend of mine was the owner of said set but they sat on a shelf for a couple of years before he used them. He then did some at home porting and installed them on his car. Not sure of the time period but one did develop some cracks. I told him to talk to Brandon and after a few conversations they were both replaced with a NEW set of heads long after the purchase. Check recent history with these heads and other than the same issues found on MOST after-market heads (tight valve guide, not the best valve job) their track record is pretty good.