I would recommend contacting Larry Barker in AZ. He has many parts and while he may not have a new or used starter, he likely has a working used one, and/or the parts to have one rebuilt. You can reach Larry at 480-843-8110. Best time I've found to call him is right around 9am or shortly thereafter (his time). You can leave a message if he doesn't answer, but I'm not sure how quickly he'll get back to you...I've had my best luck just calling as above, try again the next day if I don't get him between 9 and 9:45.
Alternatively, you can find a number of starter rebuild parts here:
http://kfparts.com/store/product-category/group-7-electrical/starter-motors-parts/Potentially you could find someone local (with the appropriate knowledge to these orphan cars) who could diagnose and rebuild your starter with the right parts.
