Originally Posted by
TonyWilliams
A properly lean mixture will also keep the engine cool, save lots of fuel, provide less "dirt" in the oil, cleaner spark plugs, smooth out the pressure in the combustion chamber, etc.
Supercharged, gas burning, 1000+ horse power radial engines during the golden age of air carrier transport didn't keep the engines cool by running richer. They'd never make it across the pond.
No they did it by burning a retarded amount of oil. Here: Oil consumption: 0.42 oz/(hp•h) and 740 hp (552 kW) at 2,250 rpm at 7,000 ft. So just for fun lets do 740 * .42 = 310.8 oz/hr convert to gallons is 310.8/128 =
2.43 gallons of oil per hour. 
Oh this is per engine by the way, so almost 10 gallons per hour with all 4.
I would like to hear the logic behind a lean the mixture to keep an engine cool? Maybe I am just reading this too literally for what you are trying to mean?