[clayfoushee]

It must be your temp. gauge or a temp. sensor problem. If you are actually running 140-50, that would mean your 160 stat is never opening, if your gauges are accurate. That would also mean the coolant is never circulating outside of your block and through the radiator. Those temps would be impossible if that were the case.

In addition, the temp. rating of the thermostat doesn't really affect the operating temp of the car, in general. Thats primarily a function of airflow and cooling system capacity.

A 160 stat is the same as a 180 stat when they are open. They just open at different temps. I prefer the 180 because it allows a car to get to operating temp more quickly from a cold start.