Rolls Royce licensed Packard to build them back in the war because Packard was the only manufacturer that Rolls would have to build "their" engines. Packard was top of the heap back then in manufacturing. Chrysler built an inverted V Motor (XIV-2220) that powered a modded XP47H to over 505mph level flight, and this was back in 45! DOA Curtiss P-60 had same prop design.