2 Strokes Down Under

hey guys new to the forum but not to 2 strokes, looking to pick up a complete rz 350 motor or pretty much anything so i can piece one together, so id be happy with either a complete 350/250 motor/ a bottom end/cases/powervalve assembly's looking at either building up a standard motor with 4mm crank or a 421 athena kit, every time i see a complete bike for sale somewhere to buy and fix up im always too late so figured i'd put my own custom bike together lol

any help would be great, thanks guys