Where FoMoCo provided engines during World War II for the unique dual-engined Traco-E&L bomber parts haulers, GM engines were conscripted into a similar service after the war.
According to Crismon, around 1947, the Eisenhauser Manufacturing Company of Van Wert, Ohio, built the above five-axle straight truck as a prototype to see whether it was possible to build a truck that “would be able to carry a 20-ton payload on the two lane US highways of the day without the disadvantages of tractor-trailer combinations.” Obviously, sans articulation between tractor and trailer, the front two axles (and, it appears, the rearmost axle) steered. Even more unique, though, was the drivetrain: two 235-cu.in. six-cylinders stacked one atop the other, driving the first and third rear axles through synchronized manual transmissions.
Crismon notes that the 1947 five-axle straight truck wasn’t built for military purposes, but its successor, a five-axle straight tanker truck, was offered to the military for testing in 1957 and designated the Model X-2. Unlike its predecessor, the X-2 used twin GMC 302-cu.in. six-cylinders laid out side-by-side and driving the first and third rear axles through Hydramatic automatic transmissions. The Army rejected the X-2 for driveability and manueverability problems.
Eisenhauer Manufacturing, btw, still operates today out of Van Wert, manufacturing metal stampings for the automotive industry and for electrical motors.