Willys MB

'The Willys MB US Army Jeep, along with the nearly identical Ford GPW were manufactured from 1941 to 1945. They are the iconic World War II Jeep.
Willys' car's designation was then changed to "MA" for Military model A. By July 1941, the War Department decided to select one manufacturer to supply them, to standardize. Willys won the contract mostly due to its more powerful engine (the Willys Go Devil engine) which the soldiers raved about, and its lower cost and lower silhouette. Whatever better design features the Bantam and Ford entries had were then incorporated into the Willys car, moving it from an "A" designation to "B", thus the "MB" nomenclature. For example, if the gasoline tank was directly beneath the driver's seat, combining the two main target areas into one, it would lessen the chance of a catastrophic hit.'
http://www.willys-mb.co.uk/