[djpateman]

Brad Penn, a successor to Kendall GT, is supposed to have the best performance of the conventional oils. It does have the additives that an air-cooled engine requires, especially our vintage engines.

I guess the oil temperature begs the question: is the engine running hotter with the lower oil temperature, or running cooler? If the oil cannot pick up the heat as efficiently the oil temperature will be lower, but the engine runs hotter. Higher temperature oil should expel more heat from the cooler, all else being equal.