There was one of the "4 speed Saganaw with a BW OD" on ebay a while back for a lot of money. I have not seen one in use, and other than reading a couple of articles and don't know anything about the conversion. I did ask a friend that has a transmission shop locally and he had not heard of them but had some serious concerns about reverse and how to accomplish the reverse lock out for the OD.
If you have a working 3 speed Saganaw/BW R10Q OD, I would install it with the electrical components and drive it. I believe you find that it meets all your requirements.
Fred
