Thats because it`s to expencive to try to get that kind of power from the smaller 396/402 motors. If you want that kind of power you`ll need a blower or NOS to to it. Your not going to do it N/A and still have a streetable ride. If your stuck with your motor, try shooting for 400-500hp, much easier to accomplish. Also, try the search option for 396/402 combos.