I have a 71 cutlass with a 350 2bbl.On the lower left front of engine just above the pan i have a Elect.sensor.Anybody know what it is.Thanks,Tom.

 

Can you post a picture? Its not a block heater is it?
I wonder if someone threaded in a coolant temp switch in the drain plug opening?

 

If it has a piece of heavy 2-conductor wire going from it to a 120VAC plug, it's a block heater.

- Eric

 

Yup, what Rob and Eric said. The 71/72 350 doesn't have any electrical sensors other than the oil/coolant senders. The block heater could be on either side of the block. Install was simple: Drain the rad, pop out one of the frost plugs and install the heater.