With summer over, and the Cali indian summer just about over... I think this just about concludes the test for this year.
So here are the Amsoil data...
I have about a half qt. left, so that would give at least another week to equal klotz in usage for the same number of days.
So to compare the results...
I'd have to say the klotz numbers are slightly better than Amsoil.
And the higher head and oil temp for both would have to be due to the higher viscosity. Yielding less oil flow to the head. So while the higher viscosity supposedly giving more protection from metal to metal contact, reduces the cooling effect of the oil.
I would say, regardless of the temperature that 40 wt. oil at operating temps is better for engine cooling.