I have a 2002 400SX that I have bumped to 450 via a Thumper Racing kit. (Short stroke, bigger piston). I love the motor with the changes, but am looking for a little more top end. I have a stock exhaust system with an FMF Q SA. I am wondering if the power bomb headers increase the top end, the bottom or both, and to what extent. I have also been told that a 520 cam adds top end.
Does anyone have any experience with these modifications?
Does anyone have any experience with these modifications?