670 needs a little more power.

I have an extra set of 40 mm carbs. Can these be bored out to 44 and who does this? Where can I find specs for the 501 rotary valve or does anyone have one. Can the stock carb boots be cut down or do I need to buy some from a different year? I think someone mentioned 93 mxz has them.\

I guess I'm looking for a set of 44mm carbs, shorter carb boots and a 501 rotary valve if anyone has this for sale let me know