as one said they would never trust any one that builds engines or would buy one built .i do not know of many bolt on heads .i would trust done. as a dealer for profiller .dart .brodixs.AFR .many others. i spent the time and money knowing what parts are worth the money . on the rotating kit ? i am not going to say any one brand of parts but many so called rotating kits are far from close as one of my warehouse i deal with stop selling them .less you need a paint shaker