The car pictured above is NOT the claimed Madman Muntz car. The "Muntz" car has a separate step-side style bed taken from a pick-up truck and, last I knew, was painted white. I believe it was a 1949 or 1950. Ray Frazier is the last person I know that owned it. The late Jim Davies of East Point, GA (outside Atlanta) owned it for years and is probably the one that made it. 30 years ago, the late John Parker told me that years before that, he was under the pick-up for some reason and recognized a weld that he had done on that car WHEN IT WAS A CAR!
There was a one page article in Cars & Parts (?) magazine in the 1970's or 1980's that showed several pics of the car, made the claim about Muntz and said that the car had a Pontiac straight eight in it at that time.
According to John Parker, Muntz never had anything to do with this specific vehicle. Muntz was a KF dealer in Los Angeles in the 1940's after WWII and maybe created a Kaiser pick-up for use at the dealership, but this car in question is not it.
On a related note: there was a Ben Walker quarterly years ago with an article by Allen Hogle (jeez, all these guys except Ray are now late. Really sad.) about Muntz and his dealership. He interviewed a then co-worker of mine (Elmer Adams) who was one of Muntz's salesmen at that time.
Sorry I was not able to find a picture of this car. Does anyone have a copy of the article? I think it may have been copied into a quarterly at some point.