The Chevrolet Bison was introduced in 1976, eventually replacing the heavy duty Series 70, 80, and 90 trucks. The GMC General was released simultaneously and eventually replaced the GMC HM-Series and JH-Series heavy-duty trucks. The Bison was available from 1977-1980. Chevrolet exited the Heavy Duty Class 8 Truck Market in 1980. GMC continued to build the General until 1988.