New Project: 1983 XC 500 - Ive got a few questions

Hi all,
Found a pretty good bunch of bikes last weekend including (2) 83 XC500's an 86 XC250 and the remnents of a 79 Can-Am 250 along with a truckload of parts and pieces from extra frames to a complete 82 WR 250 engine, wheels, forks, and misc parts...

I plan on using the best parts to restore one of the 500's and the 250, and putting the WR motor in a Yamaha Blaster Frame (by fliping and modifying the swingarm so my vertically challanged wife can finally have a Husky and park her old Yamaha Enduro long enough to restore it as well)

I'm looking for suggestions on who to look to for piston kits etc, for the 500

I'll likely have alot of extra parts once I get everything sorted out, unfortunately I got the stuff home and unloaded, which apparently made my 360 jelous which resulted in a sprained ankle before I really had a chance to go through everything on Saturday...

Anyway, if anyone has any supplier suggestions it would be greatly appreciated

Thanks in Advance,

Rodd