[Reaganwuzthebest]

The R-4360 Wasp Major was developed during WWII though it only saw service late in the war. It represents the most technically advanced and complex reciprocating aircraft engine produced in large numbers in the U.S.

I'm still a great fan of the P-51 Mustang, that was a cool fighter plane.

[PhilDragoo]

P-51 had the Rolls Royce Merlin (not a reciprocating) as did the Hawker Hurricane and Supermarine Spitfire.