140k is a bit steep, if you haven't already taken out the engine get a compression test done to check for leaks. However selling the teg and getting a brand new B18 and using the left over money to build and boost kinda sounds like a better idea than trying a 140k engine.
Any maintanance that needs to be done is alot easier while the engine is out seals, gaskets etc. Especially check the cam seal in front of the distributer as it likes to harden and leak in B-block engines. You also might want to check into seeing if the water pump, timing belt and timing belt tensioner have been replaced becasue those tend to go as well. Other than that I suggest cleaning every square inch of it before dropping it in.