Funny thing...I do alot of different type engines and the Import stuff is amazing! You set the adjusters and they tighten up like a bank vault and WILL NOT MOVE--I am told it has something to do with the metric pitch threads--If I ever prove that I am going to try it on a Mopar rocker somehow--Every Mopar aluminum rocker I have seen with the "get loose " problem seems to have been overtightened at some point and has streached the threads in the rocker--that and China adjusters are doomsday! Smith Bros adjusters are some of the best but there is no way to beat Harland rockers on a Mopar unless you go to TD or Jesel--It is crazy to race a Mopar with anything else--it will always bite you and cost MORE than good stuff at the start IMO