Bernoulli and 350 ft/s, 146 cfm/in²

I think you are correct. In an adiabatic process where no heat is transferred to the surroundings, expansion would cause a drop in temperature and compression would cause a rise in temperature.

There would be several things going on in the port (on the flow bench) that would cause temperature changes. A perfectly shaped port would diverge all the way to the throat/valve and then expand/converge into the chamber. Since the air ends up at a lower pressure in the cylinder than it starts at ambient conditions, that would tend to drop the temperature. However, because of the work being done on the fluid (air) heat would be generated. Also, any losses due to friction, turbulence and other inefficiencies would show up as heat. I think the net effect would actually be a heating of the air rather than a cooling.

Good discussion. I’ve never really thought about things in this manner.

This I have thought about: On the flow bench the air goes from a state of higher energy to a state of lower energy. That is what drives the flow direction. The energy that is lost from entry into the intake port until it exits the cylinder gets converted to heat.