Thanks Rick. It's an Edelbrock Performer dual plane, and I am actually talking about the coolant temp probe, not a sensor.
There are three ports on the intake manifold. One is right behind the thermostat which is the one I will use for the heater and temp probe. There is another smaller one right behind the disributor, do you know what that might be? And then there is one, in one of the runners, for vacuum I presume, but wonder what it would be used for other than a vac gauge.