How to Spot a Fake
Because these trucks have been off the sales floor for more than 20 years, a lot of people have worked on, customized, or modified one of them. That also means that there are a few fakes out there, and it’s important that you’re able to sort out the good from the bad.
The rarest models are usually the ones that came in the most limited runs and, therefore, are the ones most likely to be faked. The Indy 500 models are one example, but more common are the Big 10 trucks. After all, it’s easy to put a 454 in a truck and call it a Big 10, but that doesn’t make it so.
Also, the earliest years tend to be faked but for different reasons. In some states, the earlier models are still smog exempt. California, for example, requires smog checks for vehicles made in the 1976 model year or newer, so some owners swap the front ends on their trucks and even go so far as to change the VIN just to appear as if their truck were older. Always make sure to check the VIN in all locations.
When inspecting a truck, check the production date stamped in the side of the frame. If it doesn’t match with the year of the truck, say a frame stamped with “76” on a 1984 Silverado, it may be a rebuilt or salvage vehicle.
The 1976 GMC Olympic Edition was available in Canada only. It had a white base coat with a red stripe that went down the upper half of the body and came across the hood. It also had a custom Olympic emblem on the hood and stickers on the windows, and it came in the Z62 trim with chrome bumpers.
The 1976 GMC Spirit of ’76 celebrated the U.S. bicentennial. It was a white base coat with red and blue decals and custom badging on the interior. The seats were also done in red, white, and blue upholstery, with matching blue carpet.
The easiest way to sort things out is by decoding the VIN and analyzing what the truck does and doesn’t have. If you don’t know the year of the truck, there are a few tips on sorting things out correctly.
First, count the number of digits in the VIN. If there are 13 total, and the VIN is mounted on a plate in the driver-side doorjamb, the truck is a 1973–1978 model.
If the truck has a VIN on the dashboard, but it’s not 17 digits, it’s a 1979–1980 model. And if the VIN has 17 digits and is on the dashboard, it’s a 1981–1987 model. For example, should you approach a seller and he tells you that the truck is a 1973, but the VIN is clearly on the dashboard, it may be a 1981–1987 with a front clip swap. That’s quite common, as the earlier front ends are considered more desirable, so be aware.
Decoding a VIN
The 1973–1987 Chevy/GMC truck line uses a conventional 13-digit VIN system. The VIN system changed three times during the course of the Squarebody truck production run.
1973–1978 VIN Designations
First Digit: Division
| C | Chevrolet |
| T | GMC |
Second Digit: Chassis Type
| C | Two-wheel-drive |
| G | Light Duty, Forward Control |
| K | Four-wheel-drive |
| P | Forward Control |
Third Digit: Engine
| Y | V-8, 454 ci, 4-barrel carburetor (P Models) |
| S | V-8, 454 ci, 4-barrel carburetor (C Models) |
| R | V-8, 400 ci, 4-barrel carburetor |
| L | V-8, 350 ci, 4-barrel carburetor |
| U | V-8, 305 ci, 2-barrel carburetor |
| T | Inline-6, 292 ci, 1-barrel carburetor |
| D | Inline-6, 250 ci, 1-barrel carburetor |
Fourth Digit: Series
| 1 | 1/2 Ton |
| 2 | 3/4 Ton |
| 3 | 1 Ton |
| 4 | Heavy Half/Big 10 |
Fifth Digit: Body Style
| 2 | Forward Control Chassis Only |
| 3 | Cab-Chassis |
| 4 | Pickup and Van |
| 5 | Panel |
| 6 | Suburban |
| 7 | Motorhome |
| 8 | Utility |
Sixth Digit: Model Year
| 3 | 1973 |
| 4 | 1974 |
| 5 | 1975 |
| 6 | 1976 |
| 7 | 1977 |
| 8 | 1978 |
Seventh Digit: Assembly Plant
| A | Lakewood |
| B | Baltimore |
| F | Flint |
| J | Janesville |
| V | GM Truck-Pontiac |
| S | St. Louis |
| U | Lordstown |
| F | Freemont |
| 1 | Oshawa |
| 3 | GMAD Detroit |
| 4 | Scarborough |
Remaining Digits
The remaining digits are a sequential serial number, unique to the truck.