It does thread into the block, and when I took it out it showed itself to have a six-inch metal rod. The remaining coolant in the block (the radiator is drained and the head is off at the machinist) poured out. It has two wires into what looks like an insulator of sort, broken apart, and the wires are cut. I will never use the truck in the winter, so I don't think any block heating is necessary. There is a similar looking plug further back on the block, but it is only threaded about 3/8 in. Wires on that are cut as well, and the throttle spring is attached to it.
