Numbers matching

Numbers matching ? What does that mean?

In the collector car hobby, most investment-minded buyers are acutely interested in a specific car’s history. One of the main aspects of that history is an original or, as most people state it, numbers-matching drivetrain. At pedaltothemetal muscecars we feature a plethora of original and numbers-matching classics including ‘Cudas, Road Runners, Chevelles, Camaros, Corvettes and Trans Ams. And, if a potential buyer knows how to properly identify and interpret certain manufacturing codes, they can further validate their car’s history, or on request we can provide it. Numbers-matching refers to the car’s unique VIN being stamped on major drivetrain components, and with some brands Vin codes stamped on hidden places on the body of the car, thus verifying those components “authenticity” in relation to the car. That said; there are a few different variations of that definition. Some people believe the car only needs an original engine to qualify as numbers-matching. Others believe the engine, transmission and body codes all must all be stamped for the car to qualify as numbers-matching. But the generally accepted rule is a car that has both its engine and transmission are stamped, although we feel that body numbers are maybe even more important. A car can be “matching numbers” with for instance a factory installed replacement engine as in some cases the engine or transmission was swapped at the factory due to engine problems. Body vin really identify;s a car. Especialy when it matches a cars body tags or and buildsheet or windowstickers.

It wasn’t common for components of classic American cars to be VIN-stamped until the 1968 model year. That means most 30s, 40s and 50s era cars are considered original if they have an era-correct drivetrain. But as from early 1968 it became mandatory by law that all cars had vin stampings on body and drivetrains. From the factory, before that period each piece of that drivetrain is equipped with a casting and/or date code. If that casting and/or date code is correct to the time period in which the car was assembled, it is assumed to have an original drivetrain. So for instance a early build 1968 Mopar can be called factory correct without having its matching number drivetrain in place, but a 69 car normaly should have all numbers match, or factory replacement and so on.

So beginning in 1968, virtually all American cars featured major components that were VIN-stamped to prevent theft and fraud. With that in mind, it’s pretty easy to fake a simple stamp and, believe it or not, some clubs actually condone re-stamping components to create a correct appearance. This scenario is where a little bit of personal knowledge comes in. If the partial VIN stamp looks too clean, aligned or planned, it could be a re-stamp, although through our many years of seeing hundreds of cars and vins its hard to really guarantee these stamps, as even on the factory floors errors were made, stamps were “incorrect” stamped and different types and sizes of fonts were used, as well as stamps were sometimes also re-stamped on top of each other and so on. SO THERE IS NO ABSOLUTE guarantee to the numbers matching matter. Discussions on these matters, especially online are huge and everybody has a different opinion about it. But be realistic and understand that the stamping was done by human in a period in time that computer systems didn’t excist and changes accured because of change in work shifts, workers, tools and administrations. We have seen cars that were produced almost right after each other on the production line but one had many differences from the other. Also keep in mind that most car brands had different production plants for the same cars !.

We at PTTM do our best to describe our cars as good as possible but even with our knowledge its by NO means a guarantee of exact science that a car is a 100% factory correct numbers match car, as that is no longer a sure deal after 45 years… BUT if we have certain feeling, at a certain point in time, or facts that tells us that a certain car is not “original matching” we will either not state the fact or state its date correct or non of both. But again, in the end the official rule we also follow is that if the numbers we read of a block or car on the correct location that is generaly accepted MATCH the vin… we can call it numbers matching. After that its up to the buyer’s feeling and risk to make sure for himself if the car is or is not that.

And to ad some more details to the confusion. unfortunately, as with most historic things, classic car provenance isn’t an exact science. That means there are a few exceptions to the rule. For example, Chrysler’s 426 Hemis were cast in batches, with some of the blocks seeing quite a bit of shelf time before installation. And the 6.6 liter V8s for Pontiac’s ‘79 Trans Ams were assembled from stockpiled blocks cast in 1978. And also for instance, ford used some left over 390 blocks and put them in 428 cars at a time when 428 shortblocks were out of stock and we can keep going on and on. Of course, if you’re still uncertain, you can always have the numbers validated by a professional inspector like Jerry MacNeish, Galen Govier or Marti Auto Works, but again even the can maybe give an indication, but NOBODY can rule out that it might be realy incorrect or correct in the end. There is however the general rule of thumb that it has to be realistic and if you see a 1969 charger that has the Vin stamped on the block, but not on the correct pad, but lets say on the valvecover… you can assume that that car is not a true numbers matching car…

PTTM Speedshop

PTTM is an allround speedshop with more than 35 years of experience in classic cars and is specialized in American V8 cars. PTTM is a hobby based company that has evolved out of passion in muscle cars from back in the 70's.

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PTTM Speedshop

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