The only difference in the drive shafts is in material to make them, auto vs manual, and length of the cab. Engine size makes no difference. If there is any difference, it would be soaked up by the slip yoke at the front of the shaft.
The only other difference may be in the spline count between the regular M5OD and the HD version used on the 4.0. But I've never heard of or seen any mention of that anywhere, so I wouldn't even worry about that.
Interesting. I got mine from an identical truck to mine so I never really bothered to research the difference. But general rule of thumb would be to try and get one from a truck of a similar year, engine, cab config, and trans anyway so it's really not a huge deal.
Long time no update.. Life again gets in the way. Works going well, went to KOH with Ruffstuff this year and welded ultra4 cars back together which was cool. Getting ready to move soon so my focus has been elseware.
Bumper welded on, tied in at 3 points on my rear frame box with 2"x.250 wall tube and the hitch plus gussets.
Made a fuel filler neck to get the line out of the wheel well.
Made bump stops to fit into my bump cans to hold me over till i can afford hydros. 2"x.250 with 2.5" over it as a stop for the can, with a poly bump.
Cycling
Mocking up the intake
Anyone with a Hurst shifter should learn to make gaskets, as they like to leak.
After fluids maybe she'll turn over..
Rear axle is finally done with brake lines and limit straps!