Near the distributor is the thermostat housing. It has a thick coolant hose coming from it. The thermostat housing has two sensors connected to it. The one with a green harness is the ECT sensor and the one with the short skinny black connector is the ECT guage sender sensor. If you can find the housing, you need to remove 3 or so bolts holding it to the head and then you can see the thermostat.