The following historical data of the GMC C/K, manufactured by GMC, were retrieved from many sources.
GMC C/K (1988-1998)
Introduced in April 1987 as 1988 models, there were eight different versions of the C/K line for 1988: Fleetside Single Cab, Fleetside Extended Cab, Fleetside Crew Cab, and Stepside Single Cab, each in either 2WD (C) or 4WD (K) drivelines. Engines were a 4.3L V6, 5.0L V8, 5.7L V8 and a 6.2L V8 diesel. A 7.4L V8 was available in the ¾-ton and on-ton trucks.
The Work Truck (W/T) was also introduced in 1990, which featured a single cab long bed with Cheyenne trim and new grille with black bumpers. Also in 1990 the GMC 3500 EFI with a powerful 454 engine was available. The 454 EFI produced 230 hp and 385 lb-ft of torque. In 1991, the A4L80-E automatic transmission was available for the ¾-ton and one-ton trucks. In 1992, the 4-speed manual transmission was dropped and the stepside trucks were available with extended cabs. The 6.5L diesel V8 was also made available with a turbocharger. In 1993, the Sport package was made available for the stepside models, featuring body color bumpers, mirrors, and grille with cast aluminum wheels. The 700RF transmission was replaced with the 4L60-E automatic in 1993 also.
In 1991, GM introduced a 15,000 pound GVWR truck C3500HD under the GMC nameplate that was replaced by the 4500. It was marketed as a truck to bridge the gap between light duty trucks and medium duty trucks. The C3500HD was only offered as a standard chassis cab until 1996 when a crew chassis cab was also offered. It is not clear if the crew cab was for fleet orders only or if anyone could order it. An extended cab was never offered on the C3500HD. All paint colors and all but the most deluxe cab options were offered in the C3500HD. Upper cab marker/clearance lights were not optional equipment on the C3500HD.
Engine offerings for the C3500HD included three gasoline engines: 5.7L, 7.4L and in 1996 both were dropped to be replaced by the 7.4L Vortec Big Block. The 6.5L Turbo Diesel was not available till 1993. While all other C/K pickup models were dropped by 2000, the C3500HD was produced until 2002 due to demand. The 8.1L Vortec Big Block replaced the 7.4L and the venerable 6.5L Turbo diesel.
In 1994, the 6.2L diesel V8 was dropped and the trucks received grille updates. In 1995, the trucks received an updated audio system and interior. Four wheel ABS brakes were made standard in 1995 as well as driver’s side airbag on ½-ton models. The Vortec V8s were introduced in 1996, with power boosts across the board for the gasoline engines. The Vortec V8s made between 255 to 295 horsepower, thanks to high-flow cylinder heads, new camshafts, roller valve lifters and a higher compression ratio. Speed sensitive steering was introduced on the trucks in 1997 along with a passenger side airbag. 1998 saw a revision to the steering wheel and airbag system and also the addition of the PASSLOCK II anti-theft system.
[Source: Wikipedia and GMC]