Forgive my ignorance, but why does oil pump replacement require pulling the motor here?
It can be done with it in the truck from what I remember from the 100 series forum but pretty much requires just as much work because a ton of other stuff need to come out to get to it.
The 2uz is most likely the most reliable engine ever put in a cruiser (thanks Lexus for the billion dollar development in the 80s) but they don't make it easy to wrench on when things go wrong. Chebby this is not lol.