I've got one of those 4 speed Saginaws with the O.D. unit on it. I didn't build it. I bought it from one of the guys on the Inliners site. Haven't installed it yet, but one of these days it will go into my '37 1/2 ton. Seems like I remember a write up somewhere on the Inliners site about building these. Maybe in TechTips? Prowl around over there and you will probably find it.
I ran one of the Borg Warner 3sp + O.D. for about 12 years in a '57 1/2 ton. It was a great setup. Like others have posted here, I just used a toggle switch on the dash to shift it. I didn't bother with the governor and kickdown switch monkey business. Who needs it? That's just over complicating things in my opinion.
