Just be warned that that engine was a notorious, world-famous oil burner and leaker. When I was looking at options for rebuilding/replacing the engine in my 64 Gladiator many years ago, one of the options was a brand new factory "long block." The dealer said, yes, we guarantee it for everything except oil burning! When I bought my Gladiator, by the way, it was burning a quart every 25 miles! I have never before or since had an engine that could consume this much oil without a visible hole in the block.
If this is an original engine, start with the valve seals, because the original had essentially nothing there. When I did mine, you could get special spring-loaded seals, and if you still can, this might help. I replaced the valve guides on mine as well, but this is probably not necessary, and I don't know whether parts are going to be as easy to get now as they were in 1972.
Unfortunately, it seems that the block design of these engines made them also susceptible to various nasty kinds of wear and distortion. The original oil control rings were also pretty poorly designed. I did a ring job on mine with new-fangled Perfect Circle rings, and it worked perfectly for a couple of thousand miles, and then began burning oil again. A compression test showed it had perfect compression on all 6 cylinders, 140+, and it ran well too as long as I kept the plugs clean, yet by the time I traded it in it was chugging a quart every 50 miles! The dealer mechanic with whom I regularly consulted on this project suggested that it could either be a bell-mouthed cylinder, a warped block, or a bad piston, though they had been fine when I did the rings, and made no noise.
If yours is not also leaking oil prodigiously out of the front cover and various other places, consider yourself lucky. There were a couple of retrofit "anti-leak kits" made for these, one of which was a little L-shaped bracket to hold part of the front cover down.
When it's running right, that engine is surprisingly good, with more power than you'd expect, and I used regularly to get about 20 mpg, not bad on a heavy old truck. If it isn't consuming a great deal of oil, I would not worry too much. Just keep it fed. If you expect it to behave like a normal engine you'll almost certainly be frustrated.
