Pull up into the (I'm assuming nearly vertical, if dive flap-assisted) dive, reverse and now the Dauntless is low(er) and slow, never to easily get that potential energy back. Even a P-40 would be able to deal with him then (unless, of course, the pesky rear gunner gets a bead...)
A Dauntless turns real well (they were pressed into service as fighters during the Cactus Air Force days!) and can actually mix it up in a turning fight... but a P-40 shouldn't be playing that game, if you listen to Claire Chennault's wisdom. Stay fast and slash, and use that spread of 0.50s.