George Hamilton was dating President Johnson's daughter at this time. One day she decided to visit Hamilton on the set; she was being protected by the Secret Service so the whole crew saw the natural settings surrounded by armed men. Glenn Ford's son, who was playing a Civil war soldier handling a rifle, confessed later that he had to remember not to point his rifle in the direction of the President's daughter....
Several weeks into production, when Roger Corman withdrew as co-producer, he was replaced as director by Phil Karlson.
Stella Stevens turned down the female role.
Harry Joe Brown wrote a personal check to Columbia Pictures for $1,000,000 to cover the costs of going over budget.