Originally Posted by kellyefields

He might be making that at a higher psi, I bought raul (RCZs) stillen and made 20 more hp than him on the same dyno with the exact same setup minus a lightweight pulley. he made 385-390 on the mustang dyno and I believe 455 on the dyno jet. I made 405hp on the mustang dyno at a little over 7 psi at max hp so however you look at it that is close to 465-475 on a dyno jet. Simple fact is every dyno is different and every shop sets their up differently. most shops set theres to read higher because it makes the customer happier and gives them bragging rights. Dyno's are one thing a tool to help the tuner get the most out of what they are trying to tune. some tuners are conservative to ensure the final product is dependable and will last others try to get every little ounce out of the vehicle and this can lead to longevity of the system. Either way and I think someone else said it earlier it doesnt matter what numbers are put down it comes down to how happy you are at the end of the day.