See Figures 1, 2 and 3
The Vehicle Identification Number (VIN) is on a plate attached to the left hand door pillar, or on the left top of the dashboard (visible through the windshield) on later models. The gross vehicle weight (GVW), or maximum safe total weight of the truck, cargo, and passengers, is also given on the plate.
The VIN is on a plate attached to the upper left hand side of the instrument panel. The first letter indicates a Chevrolet (C) or GMC (T) vehicle. The second letter is the drive type, "C" for two wheel drive or "K" for four wheel drive. The third letter is the engine type. 1980 engine letter codes are as follows:
The first and the fourth digits in the VIN is the GVW range, 1 ( 1 /2 ton), 2 ( 3 /4 ton), 3 (1 ton) and 4 ( 1 /2 ton HD susp). The second number and fifth digit in the VIN designates the model or body style type, they are:
The fourth letter and sixth digit in the VIN designates the model year, " A " for 1980, for example. The fifth letter and seventh digit indicates the assembly plant where the truck was assembled.
The last six numbers in the VIN number are the sequential serial number.
1981 AND LATER MODELS
Beginning in 1981 a new 17 digit code is used. The interpretation is the same as previous years except that the engine code is the eighth digit. Additional engine codes include the F and H codes, 305 V8; P code, 350 V8; W code 454 V8; C and J codes, a Chevrolet built 379 cu. in. V8 diesel.