What plugs into this thingy?

[cseger1]

The thingy I am referring to is the little fitting in the block that is in the bottom left hand corner of the block in Galen's beautiful motor. The fitting right next to the shiny oil cooler pipes.

[ecomike]

Looks like an oil pressure sensor, electrical connection on top to me, but I am not sure.

[Nissan_Ranger]

Yes, it's an oil sender switch