Maybe calling the AGL-4 a Gama Goat predecessor is assuming too much. The combination of Corvair six-cylinder engine and articulated joint doesn’t necessarily lead from one to the other, especially considering the fact that GM itself was behind the former and Ling-Temco-Vought built the latter. Besides, there was at least one other Corvair-powered articulated multi-wheeler built by yet another firm for the military: the Lockheed Twister.
Like the Gama Goat, only the prototype of the Lockheed Twister used Corvair power, though in this case it used more of everything: eight wheels and dual 164-cu.in. Corvair six-cylinder engines, each running through an Allison TX-200-2B automatic transmission. Oddly, the engines sat beside the transmissions in each unit and transferred power through multiple V-belts; the transmissions then sent power through a front-mounted transfer case, which then sent power back to two differentials.
Built in October 1965 and extensively tested over the next three years by Lockheed, the prototype opened the door for a $3 million contract with the Pentagon for the production of test vehicles. Crismon wrote that the Twister “performed admirably under all circumstances;” it could easily hit 65 MPH, and the coil-sprung suspension allowed 12 inches of vertical wheel travel.
The later, larger (10 tons vs. 5.5 tons) version of the Twister that the Army tested in 1971, the XM-808, dumped the Corvair engines for two 291hp Chrysler 440-cu.in. V-8s. Three prototypes were actually built for the Army, one of which was outfitted to test the Twister’s amphibious capabilities. Crismon wrote that the XM-808 also performed well in tests, but “as a scout vehicle it was overkill, and the maintenance and cost aspects associated with the dual power train arrangements were impractical.”
At least the larger prototype still exists, on display at the Detroit Arsenal in Warren, Michigan. And all was not for naught for Lockheed when the military terminated the project: Much of the technology went into Lockheed’s Dragon Wagon 8×8 cabover truck.
More: Design and Development of the Twister Testbed, by W. Brannon, et al.