Before World War II, Continental Engines of Muskegon MI made the engines used in Graham automobiles; Graham-Paige worked with their engineers to update the prewar motor and the result was the 226 used in Kaiser and Frazer cars. The Muskegon MI plant could not supply Kaiser-Frazer and Graham-Paige (the latter had the Frazer cars built during 1946 and the first weeks of 1947) with enough motors so Continental opened up a mothballed wartime engine plant in Detroit. Kaiser-Frazer managed it, and in time took it over as the Detroit Engine Division (DED) of K-F. Kaiser-Frazer also bought the manufacturing rights to the engine as they used it from Continental so it was a Kaiser-Frazer built engine. Over the years of production the motor continued to be modified, ending up in 1954 as either an unsupercharged 118 bhp 6 or the supercharged 140 bhp 6 version. When K-F acquired the motor vehicle operations of Willys-Overland, the DED 226 in slightly different form (compared to what Kaiser cars used) started going into certain Jeep and Willys branded vehicles. By the end of 1956, the Jeep complex at Toledo had its own engine plant for the 226 and the DED equipment went to IKA in Argentina where the 226 in unsupercharged form was used in the Kaiser Carabella passenger cars.
The 134.2 cu in flathead 4 and 161 cu in flathead 6 used in Henry J and Allstate models came from Willys-Overland (which became Willys Motors after the K-F acquisition in 1953) while the Kaiser-Darrin Sports cars used the Willys F-head 6 in unsupercharged form.
Continental Engines retained ownership of the 226 design as used in Checker automobiles and other industrial applications, but many of the internal parts (pistons, rings, etc) are interchangeable with the K-F built 226's.