[Schurkey]

Originally Posted by Navy Horn 16

It's important to remember that what you get on your gauge is only reading the temperature at one point in the entire cooling system.

True.

Originally Posted by Navy Horn 16

It should be on your water crossover which is essentially your water inlet temperature. That tells you how hot the water is when it goes back into the motor.

Clearly NOT. The water crossover is the last point before the thermostat, where the coolant LEAVES the engine for the radiator. The water INLET temperature would be measured at the lower radiator hose area in the water pump.

Originally Posted by Navy Horn 16

If your cooling system is being overwhelmed, it will be really hot at this point.

Because the coolant has already picked-up heat from the engine, and is about to exit the engine to be cooled in the radiator.

Originally Posted by Navy Horn 16

So you are going to have a pretty big split between your inlet and outlet temp, which is why all these comments about needing to boil water out of your oil are nonsense. Your water temp reading isn't your oil temp, or your exhaust manifold temp, and darn sure isn't some kind of "power" equivalent. A well cooled engine runs better, lasts longer, and makes more power. I run a 160 degree thermostat, and it never gets above 175 unless I'm sitting in traffic in the summer (in Texas).

Before I got my Cold Case radiator, I got stuck in the staging lanes and did a pass with the motor around 205, and was .2 slower than the previous run. Go to a drag strip and ask people if they run their engines as hot as possible or as cool as possible.

The mistake in logic you're making is largely the result of having no practical way to keep the inlet air/fuel as cool as possible while running the cylinder block nice 'n' hot.

Cold intake air/fuel = high-density, good power, reduced detonation
Hot "short-block" = lower friction, less wear.

Folks over-cool the block trying to keep the intake manifold and cylinder head intake ports (and therefore the intake air/fuel stream) cool. As far as the intake air/fuel mix, cooler is better until you have fuel vaporization problems. It needs to be "just" warm enough to deliver a proper mix of fuel with the air to each cylinder; if it's too cold the fuel falls out of suspension in the air stream, doesn't vaporize very well, and too much goes out the exhaust unburned. Welcome to needing a choke and intake manifold heating methods in cold weather--you have to put so much fuel in the air because lots of it is not vaporized and is wasted. This is hardly a problem once the engine warms up.

Originally Posted by JLBIII

No. Both thermostats I tried were left stock.

Good. Drilling holes in thermostats is nuts unless you've disabled the OEM coolant-bypass system.

There's a reason thermostats don't come from the factory with bigass holes in them. True enough, some do have tiny stamped vents, or a "hole" that gets plugged with a "jiggle valve" when the water pump flow increases.

Any air in the system is moved to the radiator as soon as the thermostat opens the first time after cooling system service. At that point, it's seen as a "low coolant level", and the radiator is topped-off. In a properly-functioning cooling system, there is no other source of air that needs to be blown out of the engine.