Ford's pre-production model went into production as the "GP", with "G" indicating a "Government" contract, and "P" chosen by Ford to designate a car with a wheelbase of . With about 4,458 units built, the Ford GP became not only the most numerous of the pre-standardized jeeps — it was also the first jeep fielded in some numbers to U.S. Army units. The Ford's overall design and quality of construction had advantages over the Bantam and Willys models, but the GP's engine, an adaptation of the Model N tractor engine, was underpowered and insufficiently reliable. Fifty units were built with four-wheel steering, of which four have survived.