Hi Islander 2,
Sorry for the confusion, I should have clarified that the piston aircraft to which I refer were all flat engined GA aircraft. I do agree that the round engines of old were regularly operated lean of peak. It is my opinion that they are outside the scope of this discussion, as they are different enough that some operating characteristics may not be comparible.
Having reviewed your numbers, I cannot present direct evidence to the contrary, though I hold the opinion that there are too many other variables at play to allow your rationale to be considered valid in isolation. Perhaps in a test cell they would be closer to reality. I can say with confidence that in practical application, the application of carb heat to an engine which is otherwise running within the recommended operating range, will not increase the chances of detonation in any meaningful way.
If I have time, I'll fly the Teal today, (O-360) and watch it's scanner. It does not lean with great precision, but I should be able to form an opinion.
Pilot DAR