I'm almost ready to admit defeat and go with a standard size rear tire instead of my 2.75. It just looks so good. That thing is heavy as shit though, and absolutely kills my performance.
So I pulled the engine (mostly) apart yesterday and tried my hand at porting. My dremel bits kinda shit out on me at the end but I managed to enlarge the exhaust port so that it was the same size and shape as the gasket opening all the way through. When I bolted it back together though, I didn't really feel any difference, although it did run a bit better (still jetted kinda rich). My heavy rear tire and 420 chain pretty much cancel out any performance gains I would have gained.