Department > Old Iron
The Forgotten Marine
M-422 Mighty Mite
story and photos by Jim Allen
At the time it was shot, this 1960 M-422 was owned by Don Haas. The spare tire mount was a later production add-on that appeared about the time the M-422A1 appeared. The very first units did not come so equipped.
When the original quarter-ton military jeep was developed for World War II, light weight was a major requirement. The first specifications called for a 1,200 pound vehicle. That limit went up gradually when the realities of 1940 technology came to light. The standardized WWII jeep went into mass production at just over 2,300 pounds. Development of an “extra-light” 4x4 quarter-ton continued throughout the war and yielded some successful and not-so-successful designs. None made it to production directly. Fast forward a decade and the beginning of the helicopter era in American military history.
In 1950, MARCO (Mid-American Research Company) debuted a military 4x4 that weighed a mere 1,500 pounds. Ah, the benefits of new technology! Somewhere along the line, the name “Mighty Mite” was bestowed. Officially called the MARCO MM-100, it had an aluminum body, a Porsche air-cooled engine and independent suspension all around.
When comparing it to the Haas M-422, the side view of Fred LaPerriere’s M-422A1 shows the major differences between the long and short versions. Note the ribbing on the sides. Then note the extra rib next to the rear wheelwell on the ‘A1. That’s how you can tell at a glance. There’s much more leg room in the longer unit.
Here is one of the original MARCO MM-100s undergoing a “lift-test” by a Marine Corps Sikorsky H-19 chopper around 1953. The early 1,500 pound weight pretty much used up the H-19s 2,650 pound cargo limit (including crew and fuel). By the time the Mighty Mite debuted in full production, choppers were much more powerful. The Vietnam era UH-1 “Huey,” the chopper that replaced the H-19, could carry more than three times that load. Poof! A great 4x4 rendered obsolete by advances in other areas of technology.
Demonstrations of the first pilot model in 1951 impressed the Marine Corps Equipment Board enough to award a 10 vehicle contract for testing them in an air portable role. Interestingly, some of the people later involved in the Mighty Mite’s development were some of the same brains that had developed the first military jeep for Bantam in 1940, most notably Harold Crist, Chuck Hemphling and Harold Turner.
After delivery of the units in December of 1952, tests of the 10 pilot models units showed the Marines that this design was worth pursuit. One major hitch was the German-built engine. Fate intervened when it was discovered that AMC was independently developing an air-cooled aluminum V4 engine. One thing led to another and the project was shifted in 1954 to the newly formed American Motor Corporation, about the time of its merger with Hudson and name change from Nash Kelvinator. That handoff put development into the hands of a more substantial company that morphed the vehicle into a larger rig.
Development continued until 1958, when a contract for 250 vehicles was signed with the Marines... conditional on seven prototypes passing the required grueling tests. They did. What deficiencies existed were corrected and the units went into mass production in 1960. Production stopped in December of 1962 with 3,922 units built.
The heart of the Mighty Mite was this really cool AMC aluminum V4. It was air cooled and cranked out a respectable 55 ponies from just over 100 ci. Fording depth was rated at 21 inches without a fording kit and 60 inches with the kit. It used standardized 24-volt military waterproofed electricals.
Midway into the completion of a second contract for 1000 vehicles, a design change was made that increased the size of the vehicle. The M-422A1 was essentially the same rig, but stretched from 107 to 113 inches overall and the wheelbase increased from 65 to 71 inches. This allowed for more cargo volume and only an 80 pound increase in weight. According to most sources, the first 1,045 units were M-422s and the rest were ‘A1s. Some sources also cite that a certain number M-422s were converted to M-422A1s. It isn’t known if some of them were counted twice or not, so the 3,922 unit production number is subject to some debate.
The Mighty Mite’s AMC V4 had originally been designed with 95 cubic inches and to crank out 50hp. The final version made 55 hp from 108ci. Behind it mounted a New Process 4300 4-speed with an integral single speed, in-or-out transfer case. The tranny had a deep 5.24:1 first gear in lieu of a low range, but the t-case came with a built-in 1.085 underdrive. The diffs were essentially highly modified Dana 27 center sections, cast in aluminum, that contained Powr-Lok limited slips front and rear. The suspension was independent with inboard drum brakes that mounted on the diff housings.
Some things never change. One of them is the lack of comfort accorded to our fighting men. Still, the Mighty Mite was reputed to have a decent ride and better than average seats. There was plenty of room for driver and passenger, especially on the longer rigs.
In service, the Mighty Mite was an entirely successful design. It was small, light and could squeeze into places it’s bigger Jeep brothers could only dream about. While it had a relatively short time of service, it did battlefield time in Vietnam. It became historical also — ran only because helicopters got more powerful and a keeping a relatively expensive specialized lightweight rig in the inventory was redundant.
By the late ’60s, some Mighty Mites were finding their way into surplus sales and by the mid-to-late ‘70s, the Marines stopped using all Mighty Mites. They’ve been moderately popular in the military collectable realm, especially to the old Semper-Fi types. They are generally considered to be in the Jeep family, even though they are technically not “Jeeps.” Because they were built by AMC and had some of their development work done by Jeep founding fathers, they have been welcomed into the Jeep family with open arms. Prices slowly increase but parts are getting scarce.
Typical Specifications:
Engine: 108 ci V4, air-cooled, AMC AV-108-4
Power: 55 hp @ 3600rpm
Torque: 90 lbs-ft @ 2500rpm
Comp. Ratio: 7.5:1
Transmission: 4-speed, NP-4300
Rear Axle: Dana 27, w/Powr-Lok
Front Axle: Dana 27, w/Powr-Lok
Axle ratios: 5.38:1
Wheelbase: 65 in. (M422), 71 in. (M422A1)
Tires: 6.00-16
Length/Width: 107x61 in.(M422), 113x61 in. (M422A1)
Curb Weight: 1,700 lbs (M422), 1780 lbs (M-422A1)
Fuel Capacity: 12.5 gallons
Top Speed: 65 mph (55 mph military rating)
Fuel Economy: 19 mpg (Four Wheeler magazine, 1968)
Ground Clearance: 9-inches (max)
Source
D & L Bensinger Military Vehicle Parts and Restoration
610-286-9585