Ever seen this before?

[GregWeld]

I'm only going to weigh in here with some food for thought. I'm not trying to make a point - or start any arguments.


There are LOTS of cars running around that are far more powerful than what this motor is (not saying your's isn't powerful)... and these motors get RACED and raced hard.... which means that they're being spun up and held there for long periods of time... AND they're running thermostats. Including my race Mustang and Lotus.

Water only builds up pressure when it meets resistance (over simplified)... so I'd be looking at the flow of the radiator or the bottom hose being sucked closed (lacking the internal spring that is in place to keep it from doing that)... or some other simple issue that is restricting the flow other than the thermostat.