Thermostat or No Thermostat?

Check your gauge, if you are going by the stock one, they can vary alot in readings.
I actually have two gauges in my old truck, the stock one and a aftermarket.
When the stock gauge is in the middle range, the aftermarket is almost at 210.
I have verified the readings with an IR gauge, and the aftermarket one is dead on, the stock one is just a suggestion.