Bob are some of those problesm typical with after market kits?Ive also heard some of the issues have been addressed.My kid is thinking about doing a 550 kit for his 62 300.My machinist built a few strokers with their kit but I havent talked to him since he started.Im sure with you we will get an unbiased opinion.My machinist is probally one of the best in NE Ohio.There are a few members here that know him.Rocky