The VIN (vehicle identification number) is the most familiar number appearing on Corvettes. It is this number that appears on most titles (a few states have used engine numbers) and insurance policies.
A different VIN is assigned to each Corvette during assembly. Each car receives its number in sequence. The format of the number has changed over the years but the last digits always have indicated when a particular Corvette was assembled relative to others of the same year. For instance, the first 1953 Corvette VIN was E53F001001. The last was E53F001300, meaning total production for the year was 300. Note that you can determine the production quantities for each Corvette year in Illustrated Corvette Buyer’s Guide by referring to the serial sequence at the head of each chapter. But one word of caution: Four thousand Corvette VIN tags disappeared during 1973 and these cars were never built. So while the 1973 sequence goes up to 34,464, only 30,464 were built. The missing numbers were 24,001 through 28,000.
The VIN is stamped into a plate that is attached to the body of each Corvette during manufacture. The location of the plate varies with different years. From 1953 through early 1960, the plate was attached to the driver's door post. All but early 1960 models and all 1961 and 1962 Corvettes had the plate attached to the steering column in the engine compartment. The 1963 through 1967 models had the plate attached to an instrument support brace visible below the glovebox. Starting with the 1968 models, federal law mandated that the VIN be visible through the windshield from outside the car on the driver's side; so the VIN plate of 1968 and newer Corvettes is located either on the windshield pillar or on top of the dash.
To aid in detecting stolen vehicles whose serial tags have been tampered with or switched, manufacturers also stamp the VIN into several locations on the frame. Enthusiasts often uncover these numbers during restorations and all Corvettes starting with the 1953 have them.
Starting in early 1960, the sequential portion of the VIN was stamped into the engine block on a pad just forward of the passenger-side head. Comparing the number stamped into the engine with the VIN serial tag thus enables the purchaser of a used Corvette to determine if the engine in the car is the exact one installed by the factory. When Corvette enthusiasts advertise a Corvette with the statement "numbers match" they are most often referring to the match between the number stamped into the engine block and the VIN serial plate.
Unfortunately, the importance attached to engine originality by Corvette enthusiasts has led to the counterfeiting of Corvettes with engines that are not original. Since the sequential ponion of the VIN was stamped into the engine block, the surface can be milled and re-stamped. But there is another engine number you can check.
It is the date code. This will be three or four characters - a letter followed by numbers. The letter indicates the month of casting. The day is indicated by the first one or two numbers. The last number indicates the year. A date code of A122 translates to a block cast on January 12, 1962. Or 1972. Or 1982. The date code is on the top rear, passenger side of the block in Chevy small-blocks. It's forward of the starter by the freeze plug on the passenger side of the big-blocks.
The beauty of the date code is that it is part of the block casting and protrudes rather than being stamped after casting. It is very difficult to counterfeit. Attempts have been made by grinding off the original code, building up a weld bead, then shaping a new number with a pencil grinder. Extensive forgeries are rare and usually will not pass close inspection.
The reason the engine casting date is important is that it obviously must precede the assembly of the Corvette itself. There is no exact time lag and it's always a remote possibility that an engine block could get buried in inventory, but typically somewhere between a few days and two or three weeks pass between the time an engine is cast and then installed in a new Corvette .
Determining a Corvette's originality is a process of elimination. As you eliminate possible indicators of non-originality, the likelihood of originality increases. But neither you nor anyone else other than the original owner can ever be absolutely certain. As the stakes go up, so do the rewards of counterfeiting.
Some enthusiasts just entering the market for a used Corvette are under the impression that they can obtain a copy of the original sales invoice or window sticker from GM. Not true. You're on your own. This is why cars with original documentation are so prized.
If you are uncomfortable in any way about the originality of a Corvette that you're considering for purchase, either pass or get professional assistance.
