I agree with your assertion that what you showed us looks like an oil pressure sending unit or switch, but how it got into the 1/8-th NPT port on the side of the block with an elbow is a mystery ...

My 1993 Jeep Grand Cherokee’s oil pressure sensor broke, shooting 10W-30 all over the highway, leaving the engine dangerously low in lifeblood. My colleague Bradley, who was at the helm, dumped ...