Kirk Douglas was one of the few people in Hollywood who did not refer to John Wayne as "Duke" citing his dislike of nicknames. Curiously, Yakima Canutt, an expert stuntman and second unit director, and one of Wayne's oldest friends in the business, also called him "John" in most print interviews.
John Wayne, who had lost his entire left lung and several ribs in major surgery for cancer in 1964, had great difficulty breathing on an airplane while flying to the location for the start of filming and had to use an oxygen mask throughout the journey. Kirk Douglas recalled that he hadn't realized just how fragile Wayne was until this moment.
According to director Burt Kennedy, he gave up half his salary so that he could afford to hire Kirk Douglas (quoted in the Production Notes on the Universal Western Collection DVD).
According to John Wayne, the fight in the saloon was his 500th on-screen fight.
According to the production notes on the 2003 DVD release, Keenan Wynn's battered hat that he wears in the picture was Leslie Howard's Confederate cavalry hat from Gone With the Wind which Wynn purloined from MGM. Wynn first wore the hat in a 1942 MGM screen test and "wore it in every picture he made".
As Lomax is riding into Chabisco, the music coming from the saloon is an instrumental version of "The Ballad of the War Wagon."
Average Shot Length and Median Shot Length = ~5.8 seconds.
During the production, Kirk Douglas was late to the set because he was shooting a commercial endorsement for the Democratic Governor of California, Edmund G. Brown. John Wayne was furious, and was late to work the next day because he was shooting a commercial for the Republican candidate Ronald Reagan.
Length of the War Wagon: 47.5 feet, from lead horse to the back end of the wagon.
The "War Wagon" itself was built mostly of plywood and other lightweight materials, and painted to look like iron (appropriate "metallic" sound effects-such as when the "heavy" iron doors are opened and closed, etc.) were added to complete the illusion. For many years, at least through the 1980's, the deteriorating remains of "The War Wagon" were displayed in "The Boneyard" (a collection of old outdoor movie props) as part of the Universal Studios Backlot Tour in California.