It's a good 180 degree thermostat. I measured 177 deg. with a thermocouple in the radiator after the thermostat had opened. I did drill a 7/64 in. hole in it to prevent air pockets in the head as was suggested by some folks here. That also makes it warm up more slowly.

I don't have a PCV valve but I'm thinking of putting one in where the breather tube fits. I think Ralphy posted something on that.

I didn't see the Prestone green. Maybe we would all be surprised at how much water condensate gets in our oil if we don't warm it up all the time.

1948 3/4-Ton 5-Window Flatbed Chevrolet

34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.