These heads seem O.K. I don't see alot of people using them racing.In the dirt circle track world you really on see two types of heads win Dart,or Brodix.In the last couple of years a company called All-Pro has really come on the scene.I saw a set of their rasied runner 23* heads that where all CNC'D with a hand finish.These heads looked better than any other heads I had ever seen.Then I asked the price.4,500$ for them.My first car I bought cost well less than 1/2 this price.I saw these heads on a 406,Dart block, full roller, with all the good lightweight 4340 parts,16 to 1 comp. ratio on alcohol.I thought maybe 725 to 735 h.p. this combo did 768 h.p. at 7,900 r.p.m.s.The point I am trying to make is sometimes you really get what you pay for.