Temp Sending Unit
 

More newbie questions about my 1968 Sprint. It appears that I have two temperature sending units but I don't understand why? One is on the water neck and the other in the block on the opposite side. I did not trace the wires to see where they go.

The one in the second picture is the stock location on the head, not the block, I have never seen one mounted on the thermostat outlet before, interesting. I suspect you have a gauge and an idiot light hooked up. Not a bad thing in my opinion. I have modified the thermostat housing with a nipple to send warm coolant warm a base plate I had made that bolted to the bottom of the intake manifold, where the exhaust manifold normally attaches. I did this on an engine with headers, and it helped with cold weather operations. I used to drive my cars until snow actually fell, so if the temps were below freezing, it would help the engine run and idle better after the engine warmed up.

I could be wrong on this. The connection on your water neck looks like the one I had that was situated just to the side of my water neck on my intake and went to my dash cluster. The other one looks similar (not exact same) to a second temperature sending unit when I added an AutoMeter gauge. I wonder if your car had a second gauge at some point. Chasing that wire would be worth it.

Looks like an old Chevy Water Neck

I do have a gauge (inop) and just realized I do not have a functioning idiot light either. Time to chase wires. I like the idea of both but the thermostat housing is unattractive. I have a stock unit and may rely on the gauge alone.