Well,
I up-converted my clutching system, to that of an '83 IT-490. I had to replace the crank-sprocket and friction plates, as well.
The 490 start gear is machined formed from the same slab that the PRIMARY gear on the clutch basket is machined from; which is far superior to the press-fit gear. The press fitting spun and jammed the clutch boss to the basket; locking up the clutch.
I decided to go with a new basket, pressure plate and clutch boss, and thrust plates. I utilized used (but usable friction pads) and smaller hardware. I kept my steels, since they were in great shape.
The new clutch works splendidly.