It all depends on how well the combo works together. My wife's motor made 535HP on the engine dyno. She ran a 10.82 at 3130lb race weight 3 weekends ago and according to Wallace Racing Calculator that's 488 RWHP. 10% loss according to that. I know of a few other engines that were ran on the same dyno and don't produce the ET that I think they "should" run. They are more along the 20-25-30% power loss.