I had an '89 with the 351 in it. I put almost 80,000 miles on it and loved the hell out of it. It would pull a loaded two-horse trailer up the mountains to Flagstaff at 75mph (of course the gas gauge would fall as the spedo went up....but who cares) It had the C4 tranny (no overdrive) and I got around 16mpg in it. The thing ran like a beast.
The only problems I had were that the left side of the exhaust manifold would crack in cold weather (I had it while attending NAU in Flagstaff, AZ) and, after awhile, the back-door mounted tire rack would pull the door out just enough that the window wouldn't go down. You couldn't use the button on the dash, you had to go around back and push the tailgate down to get the window to go down.
That's it. Other than those two minor things I loved it. I had it in some real rough country and it worked great. Until I bought my XTerra, I lived with the regret of selling it. If its condition is good and the price reasonable, go get it.