Why not do a compression test, and see where you're at? If you don't drive it too much you could do a get-by engine job. Replace gaskets, check and tighten bearings, Maybe even just re-ring the pistons, hone, and shove them back in.
The 216 in my 1-Ton, uses a quart of oil every 400 miles or so, and has done so for the last 17,000 miles that I've owned the truck. It smokes a bit going down hill.... But oil and the occasional spark plug are pretty cheap!
