Use a cooking thermometer (needle type) to check both thermostat and temp gauge with boiling water.
A good 180 stat begins to open at 160 and is fully open at 180.

Depending on your altitude, you can calibrate the cooking thermometer right at the boiling point of water - 212* by twisting the dial face against the shaft.

Also make sure your timing and rocker arms are adjusted right.


On the road every day...
1952 Truck - 235
1948 Coupe - 261