Electric Fan thermostat mounting location question

[evolve520]

I have a 350 in my truck and want to put an electric radiator fan in. I have all the parts but I'm trying to figure where to mount the thermostat sender. I see a "port" on the driver side between plugs 1 and 2 and another on the passenger side between 3 and 4. The pass side has a thermostat in it with a a wire I assume is tied to my temp gauge. The one on the driver side has some kind of brass sender in with no wires hooked to it. Is that a good spot to put the new thermostat for the fan? Thanks,
Jon

[tincan1966]

A lot of people use one of the holes available near the thermostat in the intake manifold.

However, the most accurate would be to use one of the ones in the heads, that you mentioned. You will see less temperature variation this way, and you should stay right on your thermostat temp. If you have an adjustable fan sender module, you will want to set it about 10-15 degrees above your t-stat to kick the fan on or you can get a rapidly cycling t-stat and not very good circulation- which could cause overheating. I have had good luck using a 185 t-stat with a fan control to kick fan on at 205 and off at 185- I end up running a pretty constant 190-195 which is where my TBI engine is set up to run the best.

If you do not have an adjustable control, use a fan temp switch from a 1986 Camaro with a 305/350 TPI engine-same temp settings.

Since your driver's side seems unused, I would use it, then you can also tie in your wiring with the alternator harness over to the inner fender and have it real nice and clean.