I suppose it's like everything else with these old trucks, that is whatever you think works best. The 180 degree thermostat ran just below the middle mark of temp gauge, while the 160 degree runs right between the 1/4 and middle mark of the gauge. Even though it runs 20-25 degrees cooler now, it still runs fine with no difference in the performance of the motor. I still have good heat in the cab for 40 degree weather. If I ran it in the winter time I would have more than likely put the 180 back in. This truck doesn't see rain let alone snow LOL!!!! Other the than the position of the needle on the temp gauge, I see no difference.
