The engine is good for much more than that. If fluids have been changed, so are the transmission and differential. The differential lubricates the axle bearings by splash through the tubes and drain-back lube can pick up rust if the truck is left unused a long time in a humid climate. The rust will wear the carrier side bearings, and the outer races can spin in the housing, ruining it. Pull the caps and check for wear.
First and most critical: contain the dowel pin. TST offers a kit to do this, and replace the front crank seal while you are at it. Even if it wasn't leaking badly, it may after dragging it across the dirty nose of the crankshaft. Remove the four accessible bolts inside the case that hold the case to the block, one at a time. One is next to the dowel pin, one above the oil pump, and two are visible through windows in the cam gear when the engine is turned over to the right positions. The fifth is lower and just to the right of the window, and you can't remove it. Tighten it with a 10 mm bent open end wrench, reaching through the window.
Second and also most critical: check the exhaust manifold. Almost certainly it has shrunk about a quarter inch and is bending the outer retaining bolts. Eventually, maybe tomorrow, it will break a bolt or an ear on the head. Get a good aftermarket three-piece manifold and install it now. Use Anti-Sieze lubricant on the threads.
Things to look at: while doing the dowel pin job, check the serpentine belt, and manually rotate the various shafts/bearings: water pump, fan hub, belt tensioner, air conditioning hub. Any of them may be getting a little rough and therefore need to be replaced. The water pump is cheap and easy to replace, so I recommend doing it while in there.