88-91 GM Truck Frame Specs

by Marlin Quintana

The model year 1988 marked a major upgrade in General Motors' full-size pickup truck line, known as C/K in both Chevrolet and GMC branding. The completely reworked sheet metal body of these trucks shared the clean, boxy lines of their predecessors while appearing slightly more refined and modern. As in previous editions, the front-engine, rear- or four-wheel-drive trucks were available in a variety of configurations.

Body Styles

The two-wheel-drive C1500 and four-wheel-drive K1500 are 1/2-ton trucks with either a short 117.5-inch or longer 131.5-inch wheelbase. The short version has a 6.5-foot box while the long offers an 8-foot box. An extended cab with a wheelbase of 155.5 inches was also an option. Straight-sided trucks are known as Fleetsides in Chevy parlance, those with flared rear fenders are known as Sportsides. GMC trucks with flared rear fenders are known as Widesides.

The C/K 2500 is the 3/4-ton version of the truck while the C/K 3500 is the 1-ton version, with 'C' designating two-wheel-drive and 'K' four-wheel-drive. Both the 2500 and the 3500 have an 8-foot box, either with a regular cab or an extended cab. The heavy-duty K3500 extended-cab truck has an extra long box of 9.5 feet.


The short wheelbase C1500 is 194.1 inches long, 76.4 inches wide (plus one-half inch for Sportsides/Widesides) and 70.4 inches tall. The long wheelbase adds 18.8 inches of length for a total of 212.9. The K1500 measures the same but rides a little higher at 73.8 inches, or 74.3 inches for the heavy-duty diesel. The C2500 has a height of 73 inches, while the K2500's height is 74.3 inches and the K3500 is 76 inches tall. Length and width figures for the 2500 and 3500 regular cabs are similar to the 1500 series at 212.9 inches and 76.4 inches, respectively. The extended cab with standard box measures 236.9 inches long. The K3500 extended cab with long box measures 255.7 inches.

Other Specs

Front track for the C1500 is 63.2 inches, for the C2500 it is 62.6 inches and for the C3500 it is 63.3 inches. Two-wheel-drive trucks have a 63.6-inch rear track. The four-wheel-drive K1500 and K2500 share a 64.1-inch front track, while the K3500 front track measures 68.6 inches. Rear track is 63.5 inches for the K1500 and 63.9 inches for other K models. Turning circle varies between 43.2 feet for a C1500 short-box to 54.8 feet for an extended cab. Tire specs vary from 225/75R15 for a C1500 short-bed to 245/75R16 for a 3500-series truck. All trucks have an independent front suspension with a live axle in the rear.

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