Numbers Matching

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 RK Motors Charlotte, 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.

Numbers-matching refers to the car’s unique VIN being stamped on major drivetrain components, 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 rear unit 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 stamped.

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. From the factory, 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.

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. Always look for stampings that appear to be done in haste, as Detroit’s production lines were humming along very quickly when most muscle cars were monotonously stamped.

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.

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.