For some conceivable reason (no support by US military, Allison is not bought by a company that has money, USAAC goes even more firmly against a V12 that does not fit the 'hi-per' mantra, etc.), the V-1710 does not came about. The hi-per engines also don't materialize, as it was historically the case. How might the USAAC/AAF fighters look like after the P-35/36/43 generation is designed, especially in 1940-1942?