text: In 1958, seven prototypes passed grueling tests, and the first 250 vehicles were built by American Motors. These units went into mass production in 1960, and AMC built 3,922 Mighty Mites through 1962 for the U.S. Marine Corps. Over the years, the vehicle was produced in two model versions: the M422 and M422A1. The M422 had a short  wheelbase. After production of 1,045 units, the Mighty Mite evolved into the M422A1,  longer in both wheelbase and overall length, as well as  heavier. The first Mighty Mites with the 71-inch wheelbase were experimental models built from production M422s. They had an extended frame and aluminum bracing added behind the seat as well as crudely fashioned tool storage boxes. This model was the M422E1, of which only a few were made. Once put into production, the longer wheelbase model was designated the M422A1 and featured a reinforcing rib on the rear fender forward of the wheel opening.
  The M422 came with 6.00-16 NDT tires on steel wheels. The vehicles did not come from the factory with spare tires, but kits were later produced that could be added. However, the rear-mounted spare tires rendered the tailgate unusable. There is no provision for a gas can carrier. Either model could be fitted with a sturdier windshield similar to the Willys M38A1 that, along with top bows, would facilitate using a canvas winter top.
  At over US$5,000 per unit, it was relatively expensive,. Development and certification of the M422 took through 1959. When the M422 debuted, it coincided with the adoption of helicopters like the Bell UH-1 “Huey” with much more carrying capacity than The Marine Corps' Sikorsky H-19 with its  cargo limit (including crew and fuel), for which the M422 had been developed. Except for parachute airdrops, the vehicle became obsolete. These factors quickly rendered the Mite an outmoded, redundant supply chain complication, more expensive and largely less capable than a regular ton Jeep, which accounts for the short production period, as well as the small production total.