One of the requests for the March Military Campaign that I fielded this year came from Myron Vernis, who asked if we’d yet written about the Mighty Mite. I searched our archives to find out that not only had we not written about it, but also that I was frequently confusing the Mighty Mite with the Mutt.
It’s not that difficult to confuse the two. Besides the similar names, both were quarter-ton, four-wheel-drive replacements for the Jeep, the timelines for the two overlap, and both feature independent front and rear suspensions. But the differences between the two are substantial.
So let’s start with the Mighty Mite, above. With a development history that dates back to 1946, it predates the Mutt by several years. Engineer Benjamin F. Gregory, to pursue his concept of an ultra-light jeep, formed the Mid-America Research Corporation (MARCO) to design and build the MM100, recruiting four of the engineers who worked on the original Bantam BRC jeep. When MARCO debuted the MM100 in 1950, it used an aluminum body, a 52hp 91.5-cu.in. Porsche flat-four and sat on a 64-1/2-inch wheelbase (the Willys MB rode a 90-inch wheelbase). The unusual independent suspension used a combination of swing arms and cantilevered quarter-elliptic springs at all four corners, aluminum differentials and inboard brakes.
It performed exceedingly well in tests run by the Marine Corps, which was looking for a jeep that was light enough to be carried by helicopters to the front lines. However, it couldn’t enter production due to the foreign-sourced engine. Thus, in 1954, MARCO turned to the newly formed American Motors, which had already begun developing its own air-cooled four-cylinder engine, a 50hp 95-cu.in. V-4. AMC enlarged the engine to 108 cubic inches and in January 1960 began to fill the Marine Corps’ order for the Mighty Mite, now designated the M422. Total production over the next three years – including the lengthened M422A1 – is estimated at less than 4,000; as MARCO and AMC developed the Mighty Mite, helicopters grew strong enough to lift a standard M38 or M151, thus negating the need for an ultra-light jeep.
The M151 Mutt, on the other hand, was built to replace the M38 entirely and to introduce new vehicular technologies, such as unibody construction and coil-sprung independent suspension. Ford actually began designing the Military Utility Tactical Truck in 1951, inspired by the DKW Munga, a jeep-like vehicle that used a three-cylinder two-stroke engine. Actual production didn’t begin until 1959, with production contracts awarded to Ford, Kaiser and AM General. The engine, a typical water-cooled four-cylinder, came from Hercules and put out about 65hp (though Crismon does include a couple pictures of a turbine-powered version). The MUTT remained in production through 1982 through several iterations, including the M151A1, designed to increase load capacity; the M151A2, which corrected the infamous rear suspension design flaws that caused rollovers; and several ambulance, firefighting and gun-carrying versions. Its direct replacement was the AM General HMMWV.