Flashman....maybe the P40is your favourite plane...but:
Look at the P40, it's THICK wings, it's weight and power.
Where on earth can you get to the conclusion that it's a speedmonster?
P40 is rugged, packs a punch, and has a good rate of roll.
That's it though, - compare it to a Spit VIII which was operating in the med at the same time. Even a Spit V, not to mention a 109F or G, - once above some 15K the P40 is an UNDERDOG. Fights were taking place up to 30K+, and the one that has the alt holds the cards. 15K is medium alt. A flock of 109F's at 22K will have a P40 for breakfast.
Even the humble Hurricane was used as an escort for P40's in the med, and I put my money on the reason being altitude performance.
Then ponder on this from HiTech:
"The real problem comes when you interpet that statement to meen it had a level speed of 350 IAS at any alt. Because that number is so far from belivibilty , You would litterly have to renvent physics to ever have a plane with the HP and size of the P40 achieve that speed in level flight."
Top speed is the highest achievable speed at level flight. Look at the AH charts to see that it is not a constant. Then realise the difference between IAS and TAS.
And as a final note, Milo knows his stuff. Don't remember errors from his shop, but be aware, he has a hot temper. Reading your text makes me understand his response.
Chao.