The parts are all top notch and hand fitted as said before and he also did a mod he called PDP (Perry Directional Porting) to some. This is a port timing mod ti improve performance at high RPM. Not sure ho it effects low RPM if at all. This engine is from the pre-Schnerule (boy did I spell that wrong [sm=bananahead.gif]) at was state-of-the-art at the time. Mr Lee is one of the most acknowledged engine guru's of all time. Whatever you put it on, make sure it can stand going FASSSSSST!