[Botietruck]

Most were the 3 spd Saginaw with the Borg Warner overdrive bolted to the rear case. There were some Muncies and possibly another trans. out there, but the most popular and reliable, from what I have heard and read about, are the Saginaws. The 4 bolt side cover was the earlier non synchronized transmissions and the 7 bolt side cover units are the most sought after-they are synchronized. GM stopped putting these o/d units in trucks in 1969. I'm not sure the year they started putting the synchro. units in trucks. I have one out of a '69 truck. They're still out there and I've seen many on ebay. Parts are hard to come by, but they're there, just takes time to find them.
CG, you won't have any problems getting rid of that set up if you ever decide to sell it. If you were on the east coast, I would have been all over that one!