I have the before cam and after cam dyno sheets. That was the only thing that changed on the motor. The tune on the computer changed also. So, I guess you are partly correct in that the tune changed from a stock Roush canned tune to a custom tune, which I am sure helped gain more HP. How much more? I guess what I should have done is had them run the same tune on the before and after install but the car would barely run after they were installed, and thus needed adjustment just to idle. Cams add HP. How much?