C3 Corvette FAQ

These are the questions that come up most often in the post bag and on the forums, answered plainly. Where an answer needs a table of codes or a longer explanation, there is a link to the page on this site that carries it.

What years are C3 Corvettes?

The third generation ran for fifteen model years, 1968 through 1982. That makes it the longest running Corvette body style by a wide margin. It replaced the mid-year Stingray of 1963 to 1967, and it was itself replaced by the C4, which arrived as a 1984 model. There was no 1983 model year, so the 1982 car is the end of the line.

The year by year history goes through what changed in each of those fifteen years.

How do I decode my C3 Corvette VIN?

Cars from 1968 to 1980 use a 13 character VIN. From 1981 the Corvette moved to the 17 character format still used today. Either way the number tells you the model year, the body style, the assembly plant and the sequence number for that car.

The plant character is the one worth knowing. S means St. Louis, Missouri, where every C3 was built until the summer of 1981. The digit 5 means Bowling Green, Kentucky, which took over partway through 1981 and built every 1982.

The VIN decoder on this site will break your number down one field at a time.

Can I find the exact day my Corvette was built?

Sometimes, and it is one of the nicer things you can learn about a C3. The answer depends on which plant built the car.

St. Louis cars carry a trim tag whose build date resolves to a specific day, so you can work out your car's actual birthday. Bowling Green used a different scheme, and those dates resolve to a week rather than a single day. That covers the 1981 changeover cars built in Kentucky and the whole of 1982.

The build date decoder will do the arithmetic from your trim tag.

How do I tell the model years apart at a glance?

The bumpers do most of the work. 1968 to 1972 have chrome at both ends. 1973 is the odd one out, with a body-colour urethane front bumper and a chrome rear, and it is the only year built that way. From 1974 on, both ends are body-colour.

After that, look at the back window. Coupes from 1968 to 1972 have a removable rear window. 1973 to 1977 have a fixed vertical one. 1978 onward have the fastback glass, which is the biggest single change to the body in the whole generation.

Front fender badging helps too: no name at all in 1968, Stingray script from 1969 to 1976, and nothing again from 1977, when the crossed flags moved back to the nose. For the finer details, the year by year history and the option code list will settle most arguments.

What does numbers matching actually mean?

It means the major components on the car are the ones the factory installed, and that you can show it. In practice people are talking about the engine block, which carries a stamped pad with a suffix code and a partial VIN, and often the transmission and rear axle as well.

It matters most on the high value cars, the big blocks and the LT-1s, where it can make a large difference to what a car is worth. On a base 1977 driver it matters much less, and plenty of good cars have had a replacement block fitted somewhere in fifty years of service.

The casting numbers page and the engine identification page cover how to read the codes.

Where does a C3 Corvette rust?

People assume a fibreglass car cannot rust. The body panels indeed do not, but everything holding them up is steel, and that is where the trouble is.

Two areas matter. The first is the birdcage, the steel structure that frames the windscreen, the door openings and the roof. It rots from the inside out, usually starting where water sits at the bottom of the windscreen posts and around the rear of the door openings. The second is the frame, particularly the rails just ahead of the rear wheels, where the boxed section traps mud and salt.

Both are expensive to put right and both hide behind paint and trim that look perfectly good. If you are buying, get underneath the car with a torch and check those two areas before you look at anything else. The rust picture gallery shows what it looks like once it has gone too far.

How do I identify the engine in my C3?

Start with the stamped pad on the front of the block, on the passenger side deck just ahead of the cylinder head. It carries a suffix code that identifies the exact engine and the application it was built for. The casting number, found at the back of the block, tells you which block casting it is and roughly when it was poured.

Those two together will tell you what you have. A casting number on its own does not prove originality, since the same casting was used across several years and several applications.

See the engine identification and transmission combinations page and the casting numbers tables.

How do I find my car's original paint colour?

The trim tag on the body carries a paint code and an interior trim code. Those codes are specific to the model year, so the same number can mean different colours in different years. Always look a code up against the correct year rather than against a general list.

The paint and colour code page has the codes by year, and the RPO decoder will translate the option codes that sit alongside them.

Is a C3 Corvette expensive to run?

Mechanically it is one of the cheapest classics to keep on the road. The small block Chevrolet V8 is the most supported engine in the hobby, the Turbo-Hydramatic and Muncie gearboxes are equally well served, and there is very little on the drivetrain you cannot buy new. Ordinary servicing is well within reach of anyone who does their own spanner work.

What catches people out is body and structure work. Fibreglass repair done properly is a specialist job, birdcage rust means separating the body from the frame, and both cost real money. The engine will rarely be the expensive part of owning a C3.

Insurance is usually reasonable on an agreed value classic policy. There are some notes on that on the insurance page.

Which C3 is the best one to buy?

If you want the most car for the money, look at 1975 to 1979. They are the cheapest way into the generation, they drive much the same as the expensive ones, and the 1978 and later fastback cars have usable luggage space behind the seats. The horsepower figures from those years look poor on paper, but the cars are still quick enough to enjoy and far easier to live with than the numbers suggest.

If you want the look and the values, the 1968 to 1972 chrome bumper cars are what the market wants, with the LT-1 and big block cars at the top of that.

Whichever year you pick, condition beats specification. A sound 1979 is a far better buy than a rusty 1970, and you will spend less getting it right.

The seats are uncomfortable on a long drive. Can I do anything?

This is one of the most common complaints about the earlier cars. The seats fitted before 1978 give much less support than the later ones, and it tells after an hour or two behind the wheel.

There are two usual answers. Fit later C3 seats, which is the simplest route since the 1978 and later units were designed for the same car. Or fit Pontiac Fiero seats, a well known swap in this hobby because they are comfortable, they are cheap, and they suit the width of the C3 cabin. That one needs brackets and a bit of measuring, and it is written up in full on the Fiero seat swap page.

Are parts still available?

Yes, to a degree that surprises people coming from other classics. Between original GM stock still in circulation and a large reproduction industry, you can build most of a C3 from a catalogue. Mechanical parts are easy, interior trim is well covered, and even body panels are available.

The harder items are the year-specific details: correct date-coded components for a judged car, some of the one-year-only trim, and electrical oddities like the early fibre optic light monitoring system. Those come from specialists and from other owners rather than from a catalogue.

This site hosts the factory literature that helps you order the right thing: the parts manuals and the specification manuals for every year.

My question is not here

Send it in through the contact page and it may well end up on this page. If you want a wider audience, the C3 section of the Corvette Forum is where a lot of these questions get worked out.