The US Army/USAF DHC-4s had 2
Pratt and Whitney R-2000-7M2 Twin Wasp 14-cylinder, 1,450 hp (1,081 kW) each.
The RAAF Caribou also have R-2000s, of 1,450 HP, although which exact mark(s) seems unclear. The -7M seems, however, to have been standard from the factory.