P-36 handled well not just because Curtiss designers & engineers did a good job, it was good in that when the armament installed was pitiful, no protection for fuel tanks, basic if any protection for pilot, not using the fuselage fuel tank when combat is expected, and without necessary airframe strenthening that added weight.
The V12 engine (V-1710 in this case) will allow for considerable overboost, 60-67-70 in Hg at low altitudes (1600-1700 HP), unlike the R-1830.
The P-36 really was an American Oscar, but far better armament than the Ki-43 I, having .30 wing and .50 cowl guns. P-36 held the world dive speed record, tested for the French Hawk-75 order. It was far more robust, didn't have the wing collapse problem the Oscar had. Curtiss Model 75 had optional armored seatback offered.
But the Hawk 75 and Allison powered Model 81 could be tweaked in very high maneuvers, so Curtiss made the strong structure even more so. It got so heavy it got harder to pull those really high Gee moves.
The Long chord Wellesley cowling also gives us a clue.
The Allison-powered VG-32 was captured by the Germans two weeks before the scheduled first flight, and the VG-50 was a proposal.How about Arsenal VG-50. The Allison engine prototype crashed and the French had no money to replace it. Would've been ready in 1940 and have quite a bit of speed advantage over anything Japanese at the time.
Regarding the P&W R1830-76, when was it available to be installed on operational aircraft?
Given the above that I wrote, anything with spanking new performance is not going to be appearing in Malaya and Burma in 1941 but will barely get as far as the Middle East. Hurricanes and Buffalos were the best that was going to be spared. I note that the Hurricane was still serving over Burma in 1945.In 1941 Britain was securing itself from an invasion, maintaining a global maritime supply system, fighting a major campaign in North Africa, had just finished campaigns in the Middle East including against France, liberated East Africa and was sending supplies to the Soviet Union. Not to mention being flat broke. The gamble was being taken not to spend resources on a first class capability in the Far East as Britain was over committed everywhere else.
Given the above that I wrote, anything with spanking new performance is not going to be appearing in Malaya and Burma in 1941 but will barely get as far as the Middle East. Hurricanes and Buffalos were the best that was going to be spared. I note that the Hurricane was still serving over Burma in 1945.
Okay, then let's give the Hurri some capability.
Beard radiator, less cluttered canopy, less draggy exhausts, keep it at 8 .303s, Merlin 45, perhaps clip the wings for better rate of roll. The OTL Hurricane IIa (Merlin XX, 8 .303s) was good for 340 mph, we'd save some weight here with Merlin 45 and closely-coupled raditor group, while earing few mph (ten?) with different radiator and exhausts. A better carb would've helped also.
The Fokker DXXI and the Koolhaven FK 58 were mentioned. How would they have compared? Would they have made acceptable colonial aircraft if the ground infrastructure was sufficient?