I'm exploring options. I was hoping to fit some kind of under-drive box like the BlackBox from NorthWest Fabworks. I've been googling for a couple of hours and all I can find is some vague "23 spline" talk.

Does anybody know for sure what are the shaft specs on a gen 1, 2.6, manual KM-145 transmission:

1. transmission output shaft
a. diameter
b. spline count
c. usable/spline length
2. transfer case
a. (will be same as above)
b. (will be same as above)
c. usable/spline depth
3. any other info related (such as what adapters or cases have the same bolt pattern, what model name/number the transfer case is, etc)

87 Dodge Raider 5sp 2.6l no jet valves, Tuffpan
OME Dakar leaf springs + T-bar crank + 2" body lift (4" lift).
5500lb winch, Starion alternator, grp31 marine bat'
OBA (stock AC compressor)
33x12.5x15 Baja Claws or Wintermark extra load 235/75/15 M/S