From Chevy Wiki
The Chevrolet Bison (and similar GMC (General Motors division) General) were Heavy-duty Class 8 Truck made by General Motors between 1977 and 1988. The Bison & General were both conventional rigs. Diesel engine choices included Caterpillar Inc., Cummins and Detroit Diesel powerplants.
For some reason, the GMC version was more common than the Chevrolet version.
A GMC General with a double-bunk sleeper was featured in the 1980 movie, Smokey and the Bandit II.