WOW! Thanks much folks for all this information. I really do appreciate it. 66Sub, WetWilly, Mike B, and Crenwelge, this is all great info. You guys are steering me down the right path

It doesn't bother me to stay with the vacuum shift unit as long as I can get it to work and find all of the components, LOL....I'm thinking of going down that path. Crenwelge, I'll try to get a picture of the shift forks as soon as I can. Also, I'm going to order the 1966 and 1967 Service manual supplement tonight! This rear diff. came off of a 1967 Chevy C60 that was part of my Wife's family fleet of water trucks back then. Apparently this truck would do 60 to 65 mph, although I don't know what tranny was in the truck. Thanks again, and anymore info. would be greatly appreciated...