In 1943, any piston engined fighter plane that was to be good, needed a 2000HP engine, and I mean 2000HP at normal power. War emergency power is extra. We are looking at the RR Griffon, the Napier Sabre, or the P&W R2800.
It is worthwhile looking at fresh, new piston engined aircraft that actually were being developed in 1943. The de Havilland Hornet, the Grumman F7F Tigercat, the Grumman F8F Bearcat, the Focke Wulf Ta154, and the Mitsubishi A7M Reppu all were worked on in 1943. What was missing was the blind, screaming panic to get them in service, such as with the Hawker Typhoon in 1941.
The jet powered Me262s, Gloster Meteor, de Havilland Vampire, and the Lockheed P-80 Shooting Star all were being worked on in 1943. These were to be the next generation of fighters.
A lot of piston engined fighters developed late in the war were derived from earlier designs -- Hawker Tempest and Fury, Supermarine Spiteful, North American P-51H, Republic XP-72, and the Focke Wulf Ta152, for example. Jets were the future.