How to Decode an IHC VIN Number

by Linda Zukauskas
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truck 1 image by Chad Perry from

Until the federal government standardized all Vehicle Identification Numbers (VIN) in 1980, motor vehicle companies used their own identification systems. Not only did those systems differ from company to company but also year to year as each organization decided to improve on the conventions they were using.

Some conventions added more information that can be useful today. Other modifications to the identification system might have been useful for the International Harvester Company (IHC) internally but provide little or no value to owners today.

Step 1

Determine the year of your vehicle. Before the standardization of vehicle identification numbers in 1980, each company used its own numbering scheme and IHC was no different. Knowing the year may help you understand the structure of your VIN.

Step 2

Locate the VIN on the engine, using the flashlight if it helps to see the numbers and letters.

Step 3

Using a VIN from prior to 1940, your VIN should reflect IHC's sequence indicating when the company introduced the model followed by the number 501. For example, R100-501, R120-501, R130-501 and so on. When IHC introduced the S and A models in the mid-1950s, they added these letters into the identification sequence. They just continued the numbering with SB even after they introduced the C line in 1961. You should not see the letter C in your VIN though you may see various prefixes to indicate other models such as Scouts (FC) and Emeryville DCO-450s (W).

Step 4

Reading a VIN from 1965 to 1973, you will see a 6-digit model code with a letter to indicate where the vehicle was built followed by a 6-digit serial number. These numbers would indicate the order in which IHC made the vehicles.

Step 5

Taking a VIN from a vehicle produced after 1974 but before 1980, you'll have a five-character model code, then a letter to indicate model year, followed by plant indicator letter, a letter for production line within the plant, and a five digital serial number that started with 10001 at the new year.

Step 6

Owning a vehicle made in 1980 or later means your VIN will have three characters to indicate the country of origin, manufacturer, and type of vehicle. A 1 indicates United States, 2 is Canada. A number after this is calculated from the other characters to detect alterations to the VIN or errors in computer processing. The next character helped car owners and police determine if anyone had tampered with the VIN. This character represented the year of manufacture, starting with B and skipping I, O, and Z then a number 1 through 9. The sequence restarted in 2010 with the letter A. Again, the last numbers represent's the vehicle's position in the production line.

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