Water Temp Sending Sensor

[jterr]

HELP-I'm confused. I have a 79 and a 83 both have the PCM 351. I'm having temp issues on the 83(another post). I'm looking for the sending unit to buy and some places says it is mounted in the circulation pump, both of mine are in the part the carb is mounted on in front of coil-I think that is them.
Am I confused or is this correct for those engines

Also can I use the one from auto parts store for the 351 w engine?

Thanks