A total of 200 C-46As in two initial batches were ordered in 1940, although only two were actually delivered by December 7, 1941. At this time, one other important change was made; more powerful 2,000 hp Pratt & Whitney R-2800 "Double Wasp" engines replaced the two Wright Twin Cyclones. By November 1943, 721 modifications had been made to production models, although many were minor, such as fuel system changes and fewer cabin windows were also adopted. Subsequent military contracts for the C-46A extended the production run to 1,454 examples, 40 of which were destined for the U.S. Marine Corps, to be designated R5C-1. The military model was fitted with double cargo doors, a strengthened floor and a hydraulically operated cargo handling winch; 40 folding seats were the sole passenger accommodation for what was essentially a cargo hauler. Two C-46 were delivered from Higgins Industries Michoud Factory Field in 1942.