If you do a search you will get more reading then you want about clutches. The most popular clutches on this forum are:
Centerforce - Single disk, direct drop in replacement. Might as well keep the factory
McLeod - Dual disk, gives less pedal pressure. Some people have ran them for 3-4 years with no problem. Some have welded when pulling on track. These are kind of expensive and I can not really find much info on them. Any one have a factory direct # or dealer #? Or better yet the part # from one with ceramic disks?
South Bend - Single disk design. New pressure plate also. Seems to be the favorite on the page. A couple diffent designs to choose from and Peter is a big help.
LuK - I thik these are called Luk Gold by some. This is the brand on our factory clutch. Not a whole lot of people using them.
Sacks - Single disk. The only way to use of these is if Joe Donelly (SP?) modifiies one. I think he uses brass pucs as the friction surface.
If I missed one add it in.