Yep .... I owe it all to the MOFO Headers!!! and the DC Tune , Magnaflow, Race cats, 4.56 gears, Cal Tracs, Fidanza flywheel, Centerforce clutch, Viper slave and master, Volant Ram Air, X Metal Gen IV Shifter ( Go to their website and watch me shift!) , 170 therm, Hurst Line Lock, and M&H 390-40-17 Drag Radials. But the valve covers have never been off of my stock 2004 RC engine. Stock it dynoed 415 HP and 433 FT LBS, After headers and tune the Standard numbers were 482 HP and 526 FT LBS.