Thanks for the info
There is some weird crap happening with that truck, I'm really not sure what to figure as "Original Equipment" and "Previous Owner Modified".
It had "Z" listed as the plant, which I didn't see on the list of plants...so that was a little weird. VIN does say it was a 400 CID w/ 4BBL & 3/4 Ton.
Here's where it gets a little weird. I read on a VIN decoder site that 77 and later trucks with either 400's or 454's came equipped with TH-400 transmissions...well, this thing has a TH-350 in it, I'm pretty confident it's a TH-350.
Anyhow, I'll take a look at the transfer case tonight.