These engines are my primary choice too. R-1830 was not formally fit to the OP conditions being 2-row and 1050 HP, but it was one of options for (easily) exported and licensed DC-3, therefore in fact may be most available of all the top-notch engines.There is no wonder that US fighter designs from late 1930s featured mostly V-1710s or R-1830s while on drawing board.
Formally OP definition fit would be one-row radial Wright R-1820, meaning P-36/A5M/I-16 level of performance (i.e. obsolete by 1941).
Therefore, best choice may be to seriously considering upgrade to liquid-cooling engine later (1940+), but this require airframe design with good structural margin. P-36 has did it morphing into successful P-40 powered by V-1710.