Engine temps are down slightly after lower grill block?

[RedDevil]

FWIW, I noticed that in a headwind my LGB has the effect of LOWERING air intake temp.
All the air now has to come in through the upper grill. That's where the snorkel gets the intake air from.

When the lower grill is open less air will flow through the upper grill, and some air heated by the rad or the engine will find its way to the engines air intake. Where my cheapo in/out digital thermometer's outdoor sensor dangles to measure it.
Actually mentioned the phenomena before in this post.

[lordherald]

Originally Posted by redpoint5

With my upper grill entirely blocked, and the lower 3/4 blocked, my temps will hit 212 and the cooling fan kicks in. This is too much blockage in my opinion. I'm ok with temps reaching to 200 occasionally, but I'm not comfortable with sustained travel above that temperature.

If the car were more reliable and efficient at a higher temperature, the manufacturer would have installed a higher temp thermostat.

I have a question about this. I had a 1988 Corvette and the factory thermostat was made with a temp in the 220 degree range. At the same time the transmission was supposed to run at or above 230 Degrees. I talked to the mechanical engineer i was working for at the time. He said that they were probably trying to get rid of moisture in the engine and the trans because water would flash out of the block and the trans case above 212. He also said that his pickup truck (cant remember the make) was set up in a similar way.
So for the actual question, if the above is true why do makers set the temp to run lower that this? Are they trying to get more power by keeping the temp lower? Or is this just to stop the higher temps from coming through the firewall or is it something else altogether?