It was reported that Clark Gable, who described himself as 6'2", wore lifts to look taller than his 6'4" co-star Robert Ryan in several scenes. Gable also stood on a box to look taller than Ryan when they first see the jayhawkers.
Robert Ryan became ill with hepatitis and had to leave the production for two weeks.
Most of the long shots of Clark Gable were actually a double.
Clark Gable was never on location for the Montana scenes.