I decided to replace the original clutch after inspecting it and measuring the parts. Many were close to, or past, the minimum thickness. You can read about the procedure I used to install the new clutch in this web page:
I ordered the new clutch parts from Tom Cutter at Rubber Chicken Racing Garage who sent me the following:
21 21 1 250 035 | Diaphram Spring (Heavy Duty) |
21 21 1 251 801 | Pressure Plate |
21 21 1 236 332 | Clutch Plate |
21 21 1 231 666 | Compression Ring |
21 21 1 231 463 | Filister Head Cap Screw (6) |
Here are a couple of the pictures included in write-up.