[Rod]

Everything I can see here leads to a 1970 3/4 ton 4x4 frame and suspension.

The front diff has had at least the outside locking hubs changed.....it appears to be disc brake and 1970 had an open dana 44 front with drum brakes..making it the only year that could be changed to disc up front by changing backing plates outward. So someone either changed the brake system to disc on the outside of the diff or swapped in a newer dana 44 that being a 71- about 78 era dana 44 front. A pic of the hubs would be more clues to what year vintage the outside for the disc brake system is. Beast388 may be right on the dana 44 77-79 era..I never noticed which way the tie rod went..my 1970 have them top down...it also has flat top knuckles...in my 70 drum brake dana 44..so I'd say 1970 is the starting year of flat top.

From what you posted of the frame stamped vin its a 1970 frame built in Janesville.
Simple enough if you know what your looking at.

The transfer case is part time NP 205 ,..correct for year also and has correct style outputs from what I see.
The rear is a eaton/ corp 10 bolt style diff cover..also correct. I'd say proabby 4.57 gears ..the front tag on the front dana 44 (which it is) will more give you a ratio close to that..they werent exactly same ratio...off by a bit for handling and steering. Regardles its 4.10 or 4.57..no other choices practically. I'd bet on 4.57 in 1970.

Just looking at what I see like fan shrouds and brackets I recognize...its a 70. I'd probably know. I dream this stuff sometimes.