I'm Building up my sammy, it's an '88 brickish red soft top, bone stock.
My friends grandpa's place is basically a ghetto junkyard and his wife said I can take what I want, here's the top picks I have to choose from:
Wagoneer D44s, Chev D60 Front, 14B FF
Muncie M22 4spd, AX15 5spd
Dana 300, lot's of others but most are broken or really big heavy units (NP205, etc.)
buick regal 3.8L V6, 7.3 Powerstroke (ha, completely F'd up anyway)

I'm thinkin this setup: 3.8V6, AX15, Dana 300, D44s and use Waggy leafs

Gonna drill the 3.8 Block to accept chevy pattern, also want to chop the D44 tubes and weld on new cups & inner c's

Please feel free to criticize plans and/or make suggestions

3.8 & D300 are for sure but I can't decide between the AX15 or the M22, or if I should trade some crap for a NV4500.
I'll probably go with the D44s but a narrowed D60/14 Bolt would be sick.

The AX-15 is a medium duty transmission, but for a V6 it is probably fine.  At least it is a 5 speed where the M22 is usually a 4. 

Seems a bit heavy of a drive train for a Sammy through, especially one bone stock.  You have enough parts you could build a buggy pretty easily.