What temp thermostat came stock?

195

Two things to check before swapping the thermostat is the actual temperature of the coolant coming out of the thermostat housing when reading hot
The other is verifying what the actual temperatures are compared to what your stock gauge reads, I've had expensive brand mechanical analog race gauges read 40 F + off when warm
Never trust what you don't know to be facts, I use a Infra red hand held temperature gauge to verify now

Except that an IR thermometer can be even further off. The albedo (roughness) of the surface being measured can make a huge difference in the reading... not only that, the surface temp is not necessarily the same as the fluid or gas temp inside the object being measured!

So you also have to calibrate your IR gun to the particular t-stat housing you are measuring. I recommend a glass lab thermometer (remember those from high school and college classes?). They stay accurate unless broken.

It's like the old saying, a man with one watch always knows what time it is. A man with two watches is never quite sure...

This I agree with. Its like I cant tell you how many times I have had someone tell me the eng will run hotter without the thermostat because the coolant dont stay in the rad long enough. I have run engines over the years without the thermostat when diagnosing overheat problems and I have never seen an eng run hotter without a thermostat. It takes much longer to heat up and has never run hotter with the thermostat out. Ron

Why did big blocks come stock with 195* thermostats? Didn't small block come with 180*? I know my 68 FSM says 180* for a '68 340.