Yes, it is a Watson 43 and you are correct regarding the ratios. I have the same one in my '49 4400 ton and a half. Mine also works great although I still haven't driven it out of the yard because of engine issues. When I got my truck about 5 years ago I was intrigued with the Brownie and that was one of the reasons I bought the Big Bolt. I did some research on the internet and after several weeks of digging I wormed my way to an ancient historian at Dana Spicer who actually at one time built these things at Watson. I spent about an hour talking to him on the phone. He had old archive material on the unit that he was generous enough to copy for me. I have info that shows these units were originally used in tanks for one thing. He also sent me the installation instructions which were provided by Watson to Chevy and GMC dealers. It showed them how to make the mounting brackets to properly locate the unit so the propeller shafts could be properly connected. It also showed how to mount the shift linkage and it always was mounted on the left of the tranny shifter. There wasn't much about servicing the unit, if I remember. I put the stuff away in a file somewhere and could supply copies if someone needs them. Unfortunately some are large pages and I don't readily have a way to copy large pages.
In my installation the mounting brackets are mostly angle iron that was very obviously cut with a torch and never cleaned up so they have a lot of character. The linkage looked like it was part of a kit because all those parts are "factory" quality, not torch and hammer work. I have the bed off my truck so it is easy to see the Brownie. If anyone needs photos of my installation to help figure anything out, I could take some shots.
