I have collected a couple engines for my '41 half ton. I plan to install a 1951 216 to just make it drivable so I can work at getting the bugs out of the truck. But eventually, I have 1957 235 that I want to completely rebuild and use as my main engine. I have also collected another '51 216, a '54 235, and a GMC 228 (just for fun).
I am not going to tear into my '57 235, until I have most of the truck rebuilt.
I would be uneasy to put a lot of money and work in an engine that will sit for a couple years. (Sometimes a couple years, can turn into 8 or more).
I have to agree with "westratedel", I would try and get it running for now, and then go on to the rest of the truck. At least you will have an idea of what you have.
John