I recently bought a stock pulley and took it to a machine shop. They did some sound tests "sono-something" and determined how much metal was around the bearing. Then they took it down about 5mm. They left the grooves and he also said they "roughed it up a bit" to prevent belt slippage.

Now I need some shims because the new pully needs a bit more space to keep from rubbing the SC clutch. Any idea what size those shims are or where I can get some? After I'm done, I'll probably put it back on the dyno to check the results.