1999 Dodge Ram 1500 Question: how to tell if shelf engine is good

My 360 is burning a good amount of oil and would prefer not to sell the truck, especially considering the fact that a newer and better one worth my time will cost at least 10 grand, which I don't have. I found a used engine at a scrap shop for 500 bucks but since it doesn't have a vehicle with it I cant start to hear it run and everything. How would I go about checking it so I don't spend a lot of time and money on an engine that is in sores shape than the one I have now. Thanks for your help.