Fuel/air mixture and engine temperature

[Stingray70]

I wanted to start a thread about the effects of fuel air mixture and engine temperature in the Model A. I have read numerous other threads which touch on this. Many contain erroneous info, uneducated opinions presented as fact, and conflicting data.

My background is in aviation so I am very familiar with the use of mixture controls and internal combustion engines. I know we have many engineers, mechanics, and fellow aviators here so I am curious what you all think about this.

I recently had a discussion with a couple of very knowledgeable members of our local Model A club who gave me some suggestions regarding use of the GAV which are counterintuitive to me.

First, one local Model A expert asserted that the GAV only affects mixture at idle. My car certainly acts like the GAV changes the mixture at all speeds. Which is it?

Second, I was told by another to not run the mixture slightly more rich when driving in the hills because it will cause the engine to overheat. I thought a slightly rich of peak egt mixture gave one more power and cooler engine temperature?

Am I wrong in thinking of the GAV as being similar to the mixture control in a light aircraft?