Now I know for real, that what the acceleration sensor in my butt sensed is about right. I had my 455 Buick on the Dyno and max horsepower peaked at 215 PS which is somewhat equal to HP. If I take the 360 gross hp and deduct 20% I end up with about 290 net hp, so I am 75 ponys short. I do know only a little about the engine, as I did not built it on my own. The previous owner stated, that the heads do have the big valves and that the cam is Stage 1 also. It has a performer IM and a 69 Quadrajet, which I did rebuild and modified per the advice from Ken. The exhaust manifolds are stock and the pipes are 2.5" Ignition is converted, but no race stuff Timing is set according to the Larry-bible to 44° incl. mech and vac How would you go about in order to get the horses back? Any easy checks or fixes which you could recommend?