Duffy's Collectible Cars Blog - Your Trusted Collector Car Store For Over 25 Years.

Written by Jon Bratton
One of the terms you regularly hear in the collector car community is “numbers matching”. It’s very important to understand what this means and how it effects the selling price of a collector car. The term actually started in the Corvette circles and now has moved on to include many vehicles, but muscle cars in particular.
The most commonly accepted definition of “numbers matching” is a classic car’s VIN number matches the stamped numbers on the engine, and transmission of the car – indicating the car has its original engine and/or transmission. That’s all it really means.
In the muscle car market today, a numbers matching engine can significantly affect the value of the car – the same with the transmission although to a lesser degree. There are a few caveats to this issue that you must understand, however, before buying or selling a collector car.
1. Not all cars had VIN numbers stamped on the engine or transmission. For GM it started in (1960) with (corvettes) and for Ford and Chrysler it started in (1968). So, if your vehicle was built before these years, it won’t have the VIN number. In these situations, the next step is to determine if the type of engine in the car is correct – another subject for another newsletter but give us a call anytime for more information.
2. Where are the “numbers”? Different manufacturers and different models of cars have the VIN stamped in a variety of places. On Chevrolet’s, the numbers are stamped on the block by the passenger side cylinder head (except in 1969 when they were stamped by the oil filter for a certain period of time. Ford typically stamps on the back top side of the block and Chrysler on the bottom of the engine by the oil pan. The point is, do your research and find out where the stamp should be so you can verify any seller’s claim. Also, remember there are exceptions for various makes and models.
3. There is fraud. Because numbers matching cars can drive thousands of dollars in increased value, some cars are re-stamped. And while the numbers may match, it’s not actually the original engine. The re-stamping is typically done by milling the block to take away the old stamp and then re-stamping with numbers that match the VIN. The best way to check for this type of fraud is to ensure that the casting date on the block is 2-8 weeks older than the assembly date of the vehicle (found on the data tag of the car). If the block was cast after the assembly date, then you know it’s not the original block for the car. There are other ways to identify fraud, but this is the easiest.
If a car has number matching major components it helps define how collectible a car is and its ultimate value. At Duffy’s Collectible Cars, we check the numbers, casting dates, and engine codes on all of our vehicles so you know exactly what you are buying. If you have any questions, let us know by phone or e-mail and good luck with the purchase of your next collector car.