First Digit: Division
| C | Chevrolet |
| T | GMC |
Second Digit: Chassis Type
| C | Two-wheel-drive |
| K | Four-wheel-drive |
Third Digit: Engine
| D | Inline-6, 250 ci |
| L | V-8, 350 ci |
| R | V-8, 400 ci |
| T | Inline-6, 292 ci |
Fourth Digit: Series
| 1 | 1/2 Ton |
| 2 | 3/4 Ton |
| 3 | 1 Ton |
| 4 | Heavy Half/Big 10 |
Fifth Digit: Body Type
| 3 | Cab-Chassis |
| 4 | Pickup |
Sixth Digit: Model Year
| 9 | 1979 |
| A | 1980 |
Seventh Digit: Assembly Plant
| A | GMAD-Lakewood |
| B | GMAD-Baltimore |
| D | GMAD-Doraville |
| F | Chevrolet-Flint |
| J | GMAD-Janesville |
| K | GMAD-Leeds |
| R | GMAD-Arlington |
| S | GMAD-St. Louis |
| V | GMT&C-Pontiac |
| Z | GMAD-Freemont |
| 1 | GM of Canada-Oshawa |
| 3 | Chevrolet-Detroit |
| 4 | GM of Canada-Scarborough |
| 7 | GMAD-Lordstown |
Remaining Digits
The remaining digits are a sequential serial number, unique to the truck.
1981–1987 VIN Designations
First Digit: Nation of Origin
| 1 | United States |
| 2 | Canada |
Second and Third Digits: Division
| GC | Chevrolet |
| GT | GMC |
Fourth Digit: GVWR Brake System
| B | 3001 to 4000 |
| C | 4001 to 5000 (includes El Camino) |
| D | 5001 to 6000 |
| E | 6001 to 7000 |
| F | 7001 to 8000 |
| G | 8001 to 9000 (includes G Van Bus) |
| H | 9001 to 10000 |
| J | 10001 to 14000 |
| K | 14001 to 16000 |
Fifth Digit: Line and Chassis
| C | Conventional Cab, two-wheel-drive (1981–1986) |
| K | Conventional Cab, four-wheel-drive (1981–1986) |
| P | Forward Control Chassis, two-wheel-drive |
| G | Van, Sport Van, cutaway, two-wheel-drive |
| R | Conventional Cab, two-wheel-drive (1987–1989) |
| V | Conventional Cab, four-wheel-drive (1987–1989) |
| W | El Camino, two-wheel-drive |
Sixth Digit: Series
| 1 | 1/2 Ton |
| 2 | 3/4 Ton |
| 3 | 1 Ton |
| 4 | Heavy Half/Big 10 |
| 8 | El Camino |
Seventh Digit: Body Type
| 0 | Sedan Pickup |
| 1 | Hi-Cube/Cutaway Van |
| 2 | Forward Control |
| 3 | Four-door Cab |
| 4 | Two-door Cab |
| 5 | Van |
| 6 | Suburban |
| 7 | Motorhome |
| 8 | Blazer |
| 9 | Stake/Platform |
Eighth Digit: Engine Designation
1981 Models
| D | Inline-6, 250 ci |
| T | Inline-6, 292 ci |