Can't argue with anything Fordman777 said! Depending on the tune, and supporting mods, a Procharger at 8-9psi, will put out in the range of low 420's rwhp to high 460's rwhp. You want to tell your tuner to try to keep it around 450rwhp, or below to be absolutely on the safe side with a stock internal motor. Other than that, have fun, and be safe!