• The 2003 GMC Sierra 3500 pickup truck comes with several engine choices, with the 8.1-liter engine being the largest and most powerful option. The Sierra 3500 comes with standard equipment such as a driver information center mounted in the dash, bucket seats, automatic headlights and steel wheels.
  
  

Engine and Transmission

• The 2003 Sierra's 8.1-liter engine comes with eight cylinders and 16 valves. The engine has a displacement measuring 8,128 cc as well as a compression ratio of 9.1-to-1. The engine has a bore measuring 4.25 inches and a stroke measuring 4.37 inches. The engine produces a peak 340 horsepower at 4,200 rpm and 455 pound-foot of torque at 3,200 rpm without the aid of a turbocharger or supercharger. The truck comes with a five-speed automatic transmission that is outfitted with overdrive to work with the engine block.
  
  

Body and Chassis

• The Sierra has a body that extends a total length of 222.1 inches for the base and SLE models, 246.5 inches for the extended cab versions and 256.1 inches for the crew cab versions of the truck. The truck's body width comes in at 96.1 inches. The Sierra stands 76.2 inches tall for all trim levels, both with two- or four-wheel drive. The base and SLE trim levels have a wheelbase that measures 133 inches long, the extended cab trim levels have a wheelbase 157.5 inches and the crew cab trim levels have a wheelbase 167 inches long. The truck's front track has a width of 68.6 inches while the rear track has a width of 96.1 inches.
  
  

Occupant Area

• The Sierra's occupant area provides the front passengers with 41 inches of headroom, 41.3 inches of headroom, 65.2 inches of shoulder room and 61.4 inches of hip room. In the extended cab trim levels, the rear occupants get 38.4 inches of headroom, 33.7 inches of legroom, 66.3 inches of shoulder room and 61.5 inches of hip room. In the crew cab trim levels, the rear occupants get 39 inches of headroom, 38.6 inches of legroom, 65.1 inches of shoulder room and 62.9 inches of hip room.