In MY opinion:
I would pull the heads and check the condition of the cylinders, rotate the crank to check where the rings have rested against the walls for all those years.
Then I would pull and soak the lifters while I checked the rest.
Then pull the oil pan and check the bottom end for any moisture damage that could be cleaned up, pull the oil pump and prime it for a bit.
Pull and most likely replace the water pump.
Reassemble and go at it if all looks good.
IMHO only, OR roll the dice and watch the mess.
Angelo
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