Saturday, August 15, 2020

Is my C3 Corvette an Early or Late Model?

Someone recently asked me that question, wanting to find out if their 1976 Corvette was an early- or a late-production model.

I've heard that debate before, and the answer is one that's a bit tricky to unravel.

So, if the build date was close to when production started, that makes a C3 Vette fall into the "early" category, right?

No, not necessarily.


When Was My C3 Corvette Built?

To answer that question you have to decode the Trim tag!


Traditionally, new models are available at dealers around the fall, so the production of new C3 Corvettes was usually started in August. New 1976 Corvettes started rolling out of the factory in August of 1975.

A few times there were production overlaps. For example, the last 1976 Corvette rolled off the assembly line sometime in August of 1976, the very same month that 1977 models started production.

Your car's trim tag indicates the month and day of the month your car was built. And in the case of my '76 Vette, that was October 9, 1975.



Decoding the Trim Tag

As shown above, my '76 Corvette's trim tag specifies the month with a letter and the day with two digits. The letter C stands for the month of October since 1976 Corvette production was started in August of 1975.

In other words, A=August, B=September, C=October, and so on.

The 09 stands for the 9th day of the month which, thanks to an Internet search, I found out that October 9, 1975, was a Thursday.

But even though the trim tag shows an exact build date for my car, it does not mean that it rolled off the St. Louis, MO Corvette assembly line that very same day. The tag reflects the date when the build was started, nothing more.


Is My C3 an "Early" or a "Late" Model?

I think the "early vs. late" debate, along with the terminology, may have originated from parts vendors and not Chevrolet, and the interpretation of the terms varies depending on who you ask.

We'll probably never know for sure.

You could use the year changeover for defining which model is "early" and which one is "late." So, in the case of the 1976 model year, 1976 Corvettes built between August and December 1975 would be considered "early" models, and those built between January and August 1976 would be "late" models.

Then again, such an arbitrary approach would not apply to 1970 models, which due to a labor strike in 1969, were produced from January through July of 1970.


Defining "Early" and "Late"

Automotive parts and components are sometimes improved and/or modified while vehicles roll down the assembly line. I think this might have been the case with the 1976 radiator, for example, which was changed during production. And the same happened with the radiator core support as illustrated below in the "Rolling Model Change" page of the Factory Assembly Manual.


If this situation was applicable to your Corvette, then you would certainly want to know where your car falls within the early vs. late equation when ordering replacement parts.

In other words, if parts from 1975 production Corvettes were used in some 1976 models, and those items were superseded by a new component, then cars fitted with previous model year parts would qualify as "early," with the rest of the production run falling into the "late" category.

So I think that the "early vs. late" debate should be, therefore, strictly limited to specific components instead of the whole vehicle.

Case in point; my '76 has the long a/c compressor, whereas allegedly, other 1976 Corvettes may have the shorter unit like those in 1977 Vettes.

Ultimately, part numbers tell the actual story when it comes to parts and components, and one of the best sources for that information is the factory assembly manual, also referred to as AIM.

The AIM will list every component, along with its part number and any revisions, which will help you when ordering replacement parts. So if you own a C3 Corvette, buy the Corvette Factory Assembly Manual for your model year.



Although most of the Assembly Manual reproductions available are good and helpful if you can find an original one for your car at a swap meet or elsewhere, get one of those. In some cases, as illustrated above, some of the notes are hard if not impossible to read.


Alphabet Soup

If you want to decode other data stamped on your Corvette's trim tag, you will need help interpreting the information on it.

To do so, I suggest you visit the C3 Vette Registry, which offers a wealth of information about our cars such as statistics, C3 how-tos, VIN decoding, etc.


You can also find additional C3 Corvette VIN and trim tag information, along with a whole lot more, on C3 Corvette Land and on VetteFacts.


Fact or Fiction?

Since I am not an expert on the subject, and I tend to have more questions than answers, I am always eager to learn as much as possible about our favorite Corvettes, especially about how they were made. So if you worked at the St. Louis, MO plant back in the day, please share any insights via comment or email and I will update the article as necessary.

By the way, I later learned that the guy wanted to know if his '76 was an early or late model since apparently—and unbeknownst to me—there were two different rear bumper skins for 1976 Corvettes. Allegedly the "early" skin had a recess for the Corvette badge, while the "late" bumper skin was flat. That was news to me as I've never seen one with a recessed emblem.

Thank you for following my '76 Vette Blog!



Product Links... (#sponsored)

• Corvette Black Book | 1953-2019
• 1976 Corvette Service & Overhaul Manual
• 1976 Corvette Service & Overhaul Manual CD-ROM
1976 Corvette Assembly Manual

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