Ran across this little tale about the P-40 in the book Fighters of World War II by Jeffrey Ethel and Robert T. Sand. The book is a collection of anecdotes by combat pilots who fought in North Africa, Italy, and Great Britain.
The following tale is told by Barrie Davis, a P-51 pilot of the 325th Fighter Group:
Davis stated that new P-51 pilots that came to his group were invariably cocky to the point that they were dangerous to themselves. They felt that the Luftwaffe was finished and that they easily kill anything that flew in their P-51s. To give them an attitude adjustment the veterans of the group used a war-weary P-40. Davis was in charge of putting them through a fast, intensive training program, the final flight of which was a mock dogfight between one of the new pilots in a P-51 and any of the veteran pilots flying the P-40.
Being familiar with the strengths and weaknesses of both aircrafts, the veterans could make the P-51 look outclassed. Using the P-40s strengths, they could outfly the P-51 at low altitudes. The new fighter jocks eventually realized that there was more to aerial combat than simply having the better airplane. At that point the new pilot became ready to listen to everything the veterans had to say.