I would also not be surprised to find they are the same as Case, JD, Mitsubishi, or Yanmar, and possibly interchange with Borg-Warner 74 series transmissions and Twin Disc clutches. You'll probably have to do some leg work though.
I found a manufacture that could make me this part. I ordered 300 and split my order with Farmboy Tractors They fit perfect. Here is a link to their web site