Disconnect (pull it off) the wire going to the oil pressure sender (label it). On this car I have real oil pressure gauge as well ( the white tube) it was also disconnected.
I had als disconnected the Starter wires (green circle). The Alternator (to the right of my hand) was just removed from the block (wires are still connected).

Remember DISCONNECT THE BATTERY (ground terminal) before you touch any wires!!!!