How To Match Numbers on Your Next Car

Unless you’re buying a valuable classic car, you probably don’t give much thought to “number matching” when used car shopping. On modern cars, Vehicle Identification Numbers, or VINs, if referenced at all, are simply used to generate online vehicle history reports.

Whether you’re shopping for a 1924 Bugatti Type 23 Brescia Tourer (the first full-production multi-valve car ever made) or something as common as a 2004 Volkswagen Jetta, it’s a good idea to know some basics about matching numbers as well as be informed about the history and meaning of the VIN.

There’s a wealth of information encoded in the 17-digit modern-day VIN, but it hasn’t always been that way. To learn how to match the numbers on your next car, keep reading!

VINs were not required before the 1950s and were used only for serialization, not necessarily for identification. Checking for matching numbers on vehicles made prior to the mid-’50s can be a real challenge, but many manufacturers often etched numbers on the engine, transmission, and rear axle. Sometimes numbers can even be found on the alternator/generator, carburetor, distributor, water pump, and/or heads.

Determining what numbers need to be verified on these older cars, and their locations, can be a serious detective job that is sometimes better left to experts on a particular make and model. A true purist may only label a car “numbers matching” if all original parts are present and accounted for, but generally all numbers match if the engine and transmission are marked with the same sequence number as the chassis VIN, and the rear axle/differential’s date code and casting number also correspond with the VIN.

From the 1950s until 1980, all American auto manufacturers stamped VIN numbers on their cars and parts. The intent was to assign each new vehicle a number that would offer an accurate description of it. Over the years the number evolved to include body style, engine, and assembly plant, even including codes for body type, build date, paint color, rear end, transmission, and trim level.

Since 1980, the National Highway Traffic Safety Administration has required all new vehicles sold in the United States to have a unique 17-character VIN. That number is always placed on the inside of the dash at the base of the windshield, inside the driver’s side door jam, and even in other locations, including:

  • Firewall of the vehicle
  • Left-hand inner wheel arch
  • Steering column
  • Component parts
  • Radiator support bracket

After searching for a used car on the CarGurus Dealfinder, or anywhere else, it’s important to check the VIN in at least a couple of places before buying. While not common, it’s easy for thieves to replace the dash-mounted number of a stolen car with one from a legitimate car of the same make and model. Typically, comparing the dash-mounted number with the one placed inside the driver’s side door jam is good enough.

So, what exactly does a VIN mean? Everything you ever wanted to know about decoding the VIN is here.

Have you ever checked to make sure the numbers match before buying a used car, classic or otherwise?


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