I couldn't tell you where to get a tuned pipe specifically for your engine. Mas sells a lot of headers and pipes for all kinds of engine sizes. Try there.

Drilling the crankshaft is simple. Once you get the engine pumped up and it's really starting to make HP--you can get away with drilling out the crankshaft hole to let in more fuel.

Look at a crankshaft from the back. See the hole in the center? Thats where your fuel comes from. Everytime the piston goes up--the hole in the front of the crank opens up underneath the carb. The action of the piston going up creates a suction in the crankcase. The hole opens under the carb and it sucks in more fuel.

Once you get the engine running better, you can try to introduce more fuel to the equasion. You just drill out the hole in the crankshaft to make it bigger. Don't drill it out a lot. Find out what size it is and then go up one drill bit size. Not 1/32" or 1/8" Just go up a few thousanths of an inch. I wouldn't go up anymore than 1/64th inch--and that might turn the engine into a paperweight. You can always drill out a little bit more if you have good results. Take a bunch out of it--and you can't put it back if you screwed up. The crank is hardened steel, so you'll need a carbide bit to drill it.