Hi Bill.
Albeit it seems like you may have got a bargain, if it is oil pump, bottom end engine wear or other related issues then this may cost vastly more than possibly fitting another engine and go from there.
It would be prudent to take some true readings....e.g. oil pressure, compression, leak-down, etc to determine exactly what is going on inside the engine.
Keep up updated as always keen to know any related issues with these engines and good luck