A dealership used a total of 6 roloc scotchbrite wheels on every gasket surface of the engine during a head gasket repair. I did a combustion gas test under boost to diagnose it, then machined the decks of the block and the heads, and block sanded the other surfaces on a flat surface.
Also added a bung to move the oil temp sender from the drain plug.
Later had to remove the RH valve cover to get to a leaking turbo coolant hose.