He said of the P40 and the Bf109 (words to this effect):
The P40 was a plane of strengths and weaknesses. We learnt very quickly how to use the strengths against the slower and 'weakly armoured' Zero's. But the Bf109 was a faster aircraft which could dive as quicklly and climb faster, so in a 'dogfight', the only real advantage was a tighter turn, which is handy but won't always win out (as it didn't with the Zeros).
I'm inclined to agree with all of this (as if I would know any better anyway). But in answer to the original question, much as I would like for the P40 to have been fitted with a better engine, more suited to it's good turning & handling abilities, it was never considered as a 'serious fighter'. Just a stop gap, until they could produce the replacements.
They kept using them though.........
