I have a 160 degrees thermostat and running water and Redline water wetter, but I know if I run it hard for around 2-3 hours doing sprints and drag racing I find myself having to add about a 1/2 a quart oil and also the coolant level on the overflow decreases some. there's a slight kink in the coolant tube going into the IM.

I notice my car runs pretty well cold on a startup below normal operating temperatures. It makes me wonder if this could have anything to do with valve clearances.