Not all aircraft are equal as you have stated.
Wirraways used steel tube fuselages and fabric covering.
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The Wirraway was deliberately chosen as easy to build.
perhaps the Australians could build P-40s but it wouldn't be on a one for for one basis and the timing might be a bit late.
And you have the engine problem.
Agreed though perhaps you might get production up to the equivalent of some ratio. And they were building Boomerangs as late as 1945 (granted in quite small numbers).
This might be where the Hawk 75 actually becomes a viable option, or even an improved Aussie Hawk 75. Arguably it's a bit better than a Boomerang. If they could get Allison or Merlin engines of course, they could make some P-40s I'd think. They didn't need that many. What's more useful 700 Wirraways and 250 boomerangs or say, 200 P-40s?
Granted you do need some of those Wirraways for training probably.
As for Allison engine Mustangs. The Aileron problem might have prevented them for being great fighters but P-40s using the same engines could never have provided the photo recon capability the Mustangs provided. British still were operating two squadrons of Allison powered Mustangs on VE day.
True but they only used a few for that role. Meanwhile they were trying to fly P-51A fighter squadrons in China (to fairly dismal results) and A-36s in Italy, though maybe those were actually worth making.
The need for time machines also starts to come into play.
Which P-40 do you want them to build?
The first order for Wirraways was placed in June of 1938. The First order for P-40s was placed in April of 1939.
Similar problems with some of the other time lines. The First production P-40 doesn't fly at the Curtiss factory until April 4th 1940, 36 days before the Germans attack France.
The Army doesn't start accepting production P-40s until May (11 of them) so while a lot is known about the Hawk 75 any countries setting up to build Hawk 81s is doing so on faith, not a proven product.
Timing is everything and the Hawk 75, while good, was not good enough to displace any of the British designs form production, neither were the early P-40s.
Which leaves you with trying to change over exiting production lines rather than starting P-40 production as the production facilities are designed and built.
you are going to get more P-40s but perhaps hundreds fewer aircraft in total over the years. Is that a good trade?
Well it depends what you are trading for. I'd argue P-40s were more useful than most of those P-39s they made for US use, (including the P-400's the British gave back to us) and by say, mid 1942 it was clear that the Sun had set on the once mighty Hurricane, whereas P-40s probably still had a year left in them. Maybe enough time for some engine swaps at the very least, though I can't say. The whole thread is obviously just speculation from the OP.
But not all development and production decisions were done with optimal amounts of common sense, some course corrections could have been made which might have helped. Could you have gotten 10,000 more Hawks or P-40s in time to help? Maybe not, but 5,000 might be closer to the ballpark. Certainly 2000 or 3000. If you subtracted say 500 P-39s from the MTO and added an additional 200 P-40F/Ls that would have helped I think. The P-39s weren't doing much of anything.