Recently I have had facts we all “knew” shot full of holes. There is a series on MotorTrend called “Engine Masters.”
In episode 4 they “adjust” headers Like many of us have done in order to fit them into a car. On the Dyno this did not negatively affect the horsepower in fact during a major readjustment it improved output.
In episode 43 they ran hot then cool coolant in a test engine. I know most Tiger owners are running 160 degree thermostats, but in the 80s we just knew we made better power by keeping the engine warm. My Tiger now has had its 190 thermostat removed and replaced with 160