F4U
First flown as the XF4U-1 on 29 May 1940, and was the first US Warplane to exceed 400mph in level flight.
Initial production aircraft (F4U-1) deliveries to service started in July 1942, followed by carrier qualifications in sept of 1942. It was initially rejected by the US Navy as a carrier borne aircraft, and it was left up to the British to take the aircraft into action for the first time. It flew off of Fleet Air Arm carriers.
P38
XP-38 first flown on 27 July 1939.
Pretty cool, it was definetly ahead of its time. Pretty remarkable.
P38L had allison V-1710-111/113 engines i believe, producing 1,475hp.
P38J Had the -89/-91 engines producing 1,425 hp.
At least this is what I am getting out of my reference books, and so far they all say the same thing.
Cheers,
RTR