Hi Kenny, according to Stillen: "*Individual results will vary depending on baseline condition of the stock engine, type of dynamometer used, temperature, elevation, fuel and various other factors. Typical results are around 400HP (wheel) at under 500' elevation and below 75 degrees F. Typical output range 380WHP - 450WHP, depending on level of modification, engine age/health, elevation/sea level and the weather that particular day."