First film for cinematographer Ric Waite.

The production was a non-union shoot and used a mixture of professional and local amateur actors and crew. Most of the crew credited in the movie were local Havasu people.

The first scenes in the movie of Smokey Roberds, Hank Cappa and Andre Marquis pulling robberies were needed in order to bring the movie up the required running time, and were shot last.

The movie was shown theatrically in some locations in the United States, but played mostly as an in-flight movie, and later on TV.

Final film of Percy Helton.

The only one of Ferde Grofé Jr.'s feature films to be shot on US territory; the others were shot at various locations in the Philippines, South America and other parts of the world

The use of incendiary devices for the explosion scenes at Swansea mining town caused the buildings to catch fire.

SFX supervisor Rudy Stangler quit mid-way through the production.

Martha Hyer's last feature film.

The production team recruited actors through the town's theater guild.

Live ammunition was used by the actors in their .45-caliber machine guns at the Swansea location, necessitated by problems getting the guns to rapid-fire blanks.

Almost nothing of the buildings at Swansea in the "worker's section" used in the movie remains. Although the production used explosions and live ammunition, the buildings largely remained intact until the year 2000. The main cause of the buildings' demise was the removal of the wooden roofs for firewood, and not anything that was done during this production.

The movie was shot entirely on location, no sets were constructed.

The apartment in Malibu that Smokey Roberds robs in the beginning of the movie actually belonged to director Ferde Grofé Jr..

The person Smokey Roberds knocks out as he escapes from robbing the Malibu apartment at the beginning of the movie is director Ferde Grofé Jr.'s nephew.

First announced to star George Montgomery and Paul Winchell in the June, 21, 1967 p.15 of the Variety newspaper, to be filmed in Vancouver in July, 1967.