The Specifications for the 1989 GMC Sierra

The 1989 GMC Sierra C/K 1500 is the smallest of the Sierras. This model is available with either a 6.5-foot or 8-foot bed. Power is generated from a V-6 or diesel V-8 engine. The 4.3-liter V-6 is rated at 160 horsepower and 235 foot-pounds of torque. The 6.2-liter V-8 produces a maximum of 126 horsepower and 240 foot-pounds of torque. The only available transmission is a four-speed automatic with overdrive. The C/K 1500 comes in two cabin types: regular and extended. The curb weight varies between 3,692 and 4,912 pounds, depending on the Sierra's options, engine and trim.

The 1989 Sierra C/K 2500 is designed for medium-duty use and provides a greater payload and towing capacity than the 1500 series. Powering the Sierra 2500 is the same engine found in the 1500, either a 126-horsepower diesel V-8 or a 160-horsepower V-6. The Sierra C/K 2500 is also available in regular and extended cab versions. The truck's curb weight starts at 3,909 pounds and maxes out at 4,942 pounds, depending on options.

For heavy-duty use, there is the 1989 GMC Sierra C/K 3500. Offering the largest payload and towing capacities in the 1989 Sierra lineup, power is supplied by one of two V-8 engines. The first is a 6.2-liter V-8 diesel that produces 143 horsepower and 257 foot-pounds of torque. The second is a 7.4-liter V-8 generating 230 horsepower and 385 foot-pounds of torque. Available with an 8-foot bed, the Sierra 3500 has a curb weight ranging between 4,349 and 5,255 pounds.

The 1500 marquee represents a 1/2-ton pickup truck, the 2500 is a 3/4-ton truck and the 3500 represents a 1-ton truck. The weights do not refer to the trucks themselves but the maximum payload ratings. The 1/2-, 3/4- and 1-ton designations are an outdated system that continue to be used by the industry to help define a truck's purpose.