My personal opinion is to walk away from that truck. Period.
My cousin who is one of my best friends has a 92 F250 IDI 7. 3 with auto. In the past 2-3 years he has invested back into the truck what he originally paid for it ($7K 5-6 years ago). Cavitation got him about 2 years ago now, and the thing sat in my basement for nearly a year while he worked on it occasionally have to figure most of it out himself as two mechanic "friends" individually started helping at certain points... . then disappeared unexpectedly.

He had to have the back to cylinders sleeved, and new cylinder heads because his old ones were cracked or just to worse for wear. He spent I think between $3K & 4K just on the motor rebuild, and he really didn't do anything spectacular.
Then very shortly after he got it back on the road the trans crapped out. There went another $2800 for a Jasper HD rebuild (Goerend was out of cores, he wanted to go that route) which so far has held up great.
Oh yeah right before the motor went out a couple years back his left rear axle just walked out one day. The spanner nut? Not sure if that's it, but the threaded nut that goes on the end of the axle tube, I think it has some kind of bearings in it? Locked up, split, and became welded to his axle tube. He got it off, but the tube was deformed so he had to salvage another sterling 10. 25 rearend (Thanks MoreMPH of 2L Motorsports).
Oh yeah then there's the absolute JUNK Dana 50 TTB front axle. The pinion bearing locked up in the front axle 3 years or so back and basically destroyed everything in the front chunk. So he was 2wd in a 4wd truck for 3 years while waiting to come across a good deal on a Dana 60. Luck finally came through and he just got his straight axle conversion done about 4-5 months ago.
So he's invested more than $7K back into a $7K truck in 5-6 years?

He won't buy another truck because he "loves his truck"... . I've given up hope on convincing him, however..... he swares if that international boat anchor ever craps out again its getting a CTD! Oo. He's got a
little sense. :-laf
WALK AWAY!