by the . In 1940, Chrysler's straight six went into Massey's 201 Super, which lasted until 1942. During World War II, the flathead six was used as the basis for the Chrysler A57 multibank tank engine. The last automotive use of the Chrysler flathead inline-six was in 1964. It was replaced by the much more efficient OHV slant-6 released in the year 1958, which appeared in most Dodge trucks starting in 1961, but the predecessor of the OHV slant-6 was the 230-cubic-inch flathead six and the last automotive use of Chrysler flathead engine was 251-cubic-inch Chrysler flathead inline-six engine. According to the Standard Catalog of American Light-Duty Trucks, the Dodge Power Wagon WM300 used the 215 inline six until 1968. The Dodge WM300 was dropped for the 1969 production year. The flathead remained in production until the early 1970s for industrial and agricultural use. Straight-8 See also List of Chrysler engines References Flathead Straight-six engines Gasoline engines by model Straight-four engines