All the info I have would put your '87 5sp 4.0 Dana 35 into the same category as my '88 was when I got it - '88 5sp 4.0 Dana 35, with 3.07 gears.
I didn't even mess with re-gearing it, I took it out and it never came back. There are enough guys out there (at least up here) trying to get rid of their MJ Dana 35s that are geared at a much more desirable ratio. You could probably go pick one of them up CHEAP and just swap it in for a short term solution.