If an engine passes the compression test, and was not burning oil, I used to do what I called a "$100 rebuild" [yes, I'm older than dirt]. That is when I would take off the heads, soak them in #2 oil, de-carbonize the combustion chambers, valve faces, and piston tops with a wire brush on an angle grinder, put in a new oil pump, timing chain, water pump, fresh gaskets, then a good ignition/carb tune up. After that I had a really great running engine. Of course today's prices knock that all to 'ell but you get what I mean. I would leave a tight block alone and just refurbish everything else. The compression test lets you know if the rings and valves are good. The oil pressure test lets you know if the bearings are good. If not I stop right there before wasting money. The spark plugs will tell you if the engine has been burning oil. If nice and clean then you have a good solid engine there to expand upon.