RE: Gutted out my baja muffler and WOW
the one thing you can touch with a rotary tool in the engine and know your helping performance is polishing the crankcase, crank shaft and con rod (not the bushes for gods sake...) with a buffing wheel, just about anything else you can stuff up very easily with just a slight wobble on the dremel so i wouldn't try doing any porting work yourself until you practiced a lot on junk engines.