Donald Farr
Former Editor, Mustang Monthly
June 1, 2009
Photos By: The Mustang Monthly Archives
Sheetmetal date codes didn't include the year. Instead, the code provided the month and day of manufacture, the plant, and the shift. This "7 15 C3" stamping on a '65 Mustang front fender reveals that it was made on July 15 at the Cleveland stamping plant during the third shift.

So is there a legal definition of matching numbers? "Not necessarily," Alcazar says. "But you realize how ambiguous some of the descriptions are by getting placed in the middle of what is essentially the buyer's discovery duties and the seller's disclosure. It's amazing when people spend hundreds of thousands of dollars in attorney fees trying to figure out the definition of that ambiguity."

Matching numbers cars are collectible because they are much rarer than non-number matching cars. They also represent a look back in history, which is what ties matching numbers to collector car values. As years go by, matching numbers Mustangs are going to become rarer and even more special. "As parts wear out or vehicles are damaged, fewer Mustangs will be numbers matching in the future," says Marti. "As this ever-shrinking survivor group moves more into the realm of historical icons, I hope owners will do their part to conserve, protect, and preserve the herd."

Boiled down, matching numbers only matter if you're serious about concours or you're talking serious bucks for a collector-type Mustang. If you've got a regular '67 hardtop or '73 convertible and you can point to correct date codes and show off the original bill of sale, that's great from an interest standpoint. But it likely won't get you thousands of dollars extra when you sell it.

Major components like steering boxes were identified by stampings on tags. Because '65-'66 GT Mustangs came with a quicker steering ratio, they need to have the quick-ratio steering box, as the HCC-AX here indicates. The "5K25B" date code breaks down to October 25, 1965, second shift.

Still, Ed Meyer isn't so sure about matching numbers. "A lot of people stay away from the subject because there are so many variations between years, makes, and models. You're probably opening up a can of worms."

Four Legs Of The Stool
As president of Russo and Steele Collector Automobile Auction, Drew Alcazar has his own unique spin on matching number Mustangs. He sees it as four distinct levels, or "legs of the stool."

Numbers Matching: "The lowest level is numbers matching. That means someone assembled a group of parts that in theory would have been made in a window of manufacturing opportunity that would say, 'Yes, these parts were born about the same time as the car.' If you have a block that's dated in the third quarter of '68 in a car that was made the first quarter of '68, you've got a problem because the car was born before the engine. It's not easy but with enough tenacity, wherewithal, and dedication, a guy can figure out a way to put together a block made within the quarter that his car was, a couple of heads that were cast a couple of weeks within the block's casting date, and a carburetor manufactured during the previous quarter or half year as the car. In theory, these parts were born at the same time or before the car. So numbers matching means you have parts that are correct for the car."

Original numbers matching: "This means the parts were installed on the car when it went down the assembly line. This is the engine that went into the engine bay, these are the heads that were bolted to the engine, this is the manifold and carburetor that was bolted on top of it. This is the sheetmetal that was destined to be a GT350 or shock towers that were formed and the body bucked to be a Boss 429. It's like being kind of pregnant-you either are or you ain't."