By Mike "Doc" Cobine
18 December 1996 Updated June 28, 2004
Matching numbers is a term tossed about with ease, as is
restoration. Both are found in most Corvette ads today as an indication that
this Vette is somehow better to buy than one without. This document will
attempt to clarify some of the issues and show how to determine what matching
numbers really are.
Restorations, Inflation, and
Investments
Car restorations have been going on for many years. It is not a
new fad, and yet it is, since suddenly it is in vogue to restore a car,
especially a Corvette, for resale. Part of this was the appreciation of the
value of the restored car compared to the appreciation of your money in the
bank. Due to inflation eating a person's savings in the bank, many invested in
cars as the selling price could be adjusted to compensate for the rise in
inflation.
While
some performed restorations on Corvettes in the '60s, most were unknown and
were not completely to factory specifications due to an inability to obtain
factory original parts. As used Corvettes were quite cheap in that era,
investing heavily in parts was for the love of the car only and often shortcuts
and compromises were made to functional and correct appearing items.
Most
antique car restorers by this time were concentrating on great detail in
restoring cars, as to not just correct in appearance, but correct in parts,
such as the original bolts with the original head patterns, original
upholstery, and so on. In the mid '70s, David Burroughs restored a '65 Corvette
and started a standard for others to follow. While his book makes it seem like
this was a monumental event, the reality is that his car was virtually in
"like new" condition, still having factory stencils and chalk marks
intact on the frame. Much of the restoration of the chassis was thorough
cleaning to preserve the original items, where most attempting restoration on a
10 year old or older Corvette usually finds 10 years' worth of rust, dirt, and
gunk from daily driving. Still his book set a standard that the better than
factory show appearance given many Corvettes of the era was not the appropriate
manner to restore one, but to give detail to factory markings, factory
imperfections, and make it appear the way the factory built it.
With
the National Corvette Restorers Society and the Bloomington Gold groups giving
direction and a place to shine for restorers, restorations began in earnest for
Corvettes in the '70s. With all the hard work and material involved, these cars
began to command a higher price than the typical Corvette of the era that was
driven and maybe modified extensively. With each restored Corvette came more
interested people who willingly paid higher prices on cars and thus the price
of Corvettes began climbing. In 1970, many early Sting Rays could be found from
$1200 to $2000. In 1974, most Sting Rays could be found from $2000 to $4000. By
1976, restored or original 1963 coupes were commanding as much as $8,000
(although most Sting Rays were still in the $2500 -$4500 range). This climb was
noticed and many began to invest, such that by the mid '80s, the prices were
climbing to unbelievable heights.
Just What is Restoration?
In the strictest sense, restoration is returning the car to a
previous form. Most restoration groups believe that unless the car is restored
to some historical significant form and event, such as the 1963 Grand Sports or
some race cars, the car should be restored to the way it left the factory. This
means exactly the way it left the factory, not how it could have left.
Restoring a 1963 coupe 300 hp Sting Ray means returning it to exactly the way
it left, with the original parts preferred and correctly-dated and numbered
parts if the originals are not available. Making it a 360 hp fuel injected
coupe is not restoring it, even if all correct parts are used, as it was never
a 360 hp coupe. It cannot be considered original if it was never that to begin
with.
Creating
a 360 hp coupe from a 300 hp coupe is a counterfeit. While there is nothing
wrong with creating any car you wish, as this was the basis of all car
customizing, it is wrong if the intent is to defraud a buyer or show judge by
passing off a 300 hp coupe as a 360 hp coupe.
When
prices rose drastically in the mid '80s, the 1967 coupes with the 435 hp engine
were approaching $100,000 in price while 300 hp coupes were around $30,000.
This led to many cars being counterfeited from 300 hp versions to 435 hp
versions. Depending on the skill of the counterfeiter, the buyer may never know.
However, they are still fakes.
Today,
the NCRS uses judging guides that clarify what is right and wrong on any given
car. There are still exceptions that they miss, as being a production car,
changes occurred and workers didn't follow the "rules" when installing
parts. But for the most part, the judging guides are the best source of how to
determine whether a car is authentic or a fake.
As
such, the strictness of the rules in true restoration is that even though you
hate that green or red interior, you cannot change it. The same holds true with
that Burnt Orange or the Arctic Blue paint. For this reason, the creative ways
of custom cars holds a definite appeal. If you buy an orange Corvette with
green interior, and hate the color, you can repaint it black with a white
interior, or white with a saddle interior, or however you like.
If
you really want an L88, but can't find one or afford the $100,000 price someone
is asking, then build your own. I built an L88 engine for $2500. You can easily
build an exact factory replica engine for under $5000 and have 550 horsepower
under your hood.
Customizing
has one rule - make it how you like it. But be prepared for many to give you
grief over your choice as it is not "restored". Restoration has many
rules and you must adhere to all of them or the car is not restored.
Restoration can be very expensive due to the man-hours and expenses incurred.
This is part of the reason for the high prices of restored Corvettes.
One
final thing to remember - matching numbers and date codes do not make a car run
better, longer, faster, or anything. It merely means the car is the same as
when it left the factory. In many cases, you may find a restored Corvette runs
worse than its unrestored counterpart as modern technology in items like tires,
brakes, shocks, and so on has advanced for a good reason - the old stuff was
not very good compared to today's parts. If you are a history buff wanting to
preserve history or an investor who wants to make a buck, then you must ensure
the car you buy is restored fully or ensure that you restore it fully to sell.
If you are a Corvette enthusiast who desires performance and fun, then
restoration is a very expensive path to what can be obtained in many cheaper
ways.
So What
Are Matching Numbers?
Many claim matching numbers for their Corvettes but most have no
idea what this really means. Once matching numbers meant that the parts were
the correct ones for that car. In the case of the matching numbers on the
block, including the partial VIN on the stamp pad, this implied originality. A
car that had a matching numbers block had the original block. However, there
have been cases for several years of counterfeit number pads. Now NCRS does not
consider that to be counterfeit, but restoration. So if you find the numbers
including the VIN on the engine pad matching, you need a lot more proof that
this engine is really original. It may just be a restamp. Buyer Beware!
There are many levels of numbers that should match, and I'll
list some of them here.
|
|
Body |
|
VIN |
The Vehicle Identification
Number of your car. From '53 to '60, it is in the driver's side door jam.
From '60 to '62, it is on the steering column in the engine compartment. From
'63 to '67, it is under the glove box. From '68 to '82, it is in the driver's
side windshield pillar. |
|
|
Engine |
|
Casting Number |
The part number cast into the block when made.
See Engine Block. |
|
Casting Date |
The date of the casting of the block.
See Engine Block. |
|
Partial VIN |
Stamped on the engine pad located in front of
the right head. An engine identifier is also stamped here. See Engine
Block. |
|
|
Bellhousing |
|
Casting Number |
The part number cast into the
right side near starter. |
|
|
Transmission |
|
Casting Number |
Part Number cast into the case
and tailshaft when made. |
|
Date code |
Usually the casting date is in
the body but this is the case date. The assembly date is stamped in as part
of identifier code. |
|
Partial VIN |
Stamped along top of mounting
ear in some, along joint of main case, or on a raised pad in the main body
(newer T-10). |
|
|
Rear End |
|
Date code |
Cast in drivers side of housing
for the case of '63-'79. In straight axle '53 to '62 Corvettes, the
identifier is stamped on the front right side. In the IRS, the assembly date
is stamped in identifier on the bottom flange. |
|
Gear ratio |
Stamped in bottom flange as part
of identifier as a letter code, such as AW. |
|
|
Alternator/Generator |
|
Part Number |
Stamped on top with date and
amperage rating. |
|
Date Code |
Stamped on top along with
amperage rating and part number. |
|
|
Water Pump |
|
Casting Number |
|
|
Casting Date Code |
Cast on front of the pump. |
|
|
Radiator |
|
Part Number |
Stamped in aluminum, embossed in
copper. |
|
Date Code |
Stamped in Aluminum. |
|
|
Distributor |
|
Part number |
Stamped in aluminum housings and
embossed on a tag on iron units. |
|
Date Code |
Same as Part Number |
|
|
Window Glass |
|
Date Codes |
Each window has its own as part
of the marking. |
|
|
Carburetor |
|
Date Code |
Either on brass tag or stamped
in air horn or body, depending on the carb. |
|
Part Number |
Either on brass tag or stamped
into air horn or body, depending on the carb. |
|
|
Fuel Injection '57-'65 |
|
Part Number |
Stamped on a metal tag on the
left front of the plenum. |
|
Date Code |
|
|
Serial Number |
Stamped on side of Plenum for
the first hundred or so in 1957 and then were stamped on the metal tag. The
serial number does not have to correspond to the car's serial number. |
|
|
Heads |
|
Casting Number |
Usually cast on top under rocker
arms. |
|
Date Code |
Usually cast on top under rocker
arms. |
|
|
|
|
|
|
Casting
Numbers
When a part is cast, the mold has a part number and a date code
set so that it is part of the mold and the part is forever identified. Most
older Corvette parts such as heads, blocks, and manifolds, usually have a 7
digit casting number beginning with 3 to identify the part.
|
On
most blocks, the casting number is located on the bellhousing flange behind
the driver's side head. The casting number does not usually correspond to any
engine part number as the engine part number is for the assembly, not the
casting. |
|
|
|
Cylinder Heads The
casting number is usually in the area under the rocker arms. Years of baked
oil may fill the numbers to make them hard to read. On some heads, partial
numbers were found on the intake runners on the block side, such as the 461
and 462 heads. |
|
|
|
Intake Manifolds Usually
on the rear runner on top. |
|
|
|
Exhaust Manifolds Usually
on the outside of the manifold. Small block Ram Horn manifolds usually have
this on your left as you view them. The big block manifolds are down the
side. |
|
|
|
Transmission Casting
numbers are on both the main body and the tailshaft housing, usually on the
right side. |
|
|
|
Rear End The
casting number is located on the right side near the prop shaft. |
|
Water Pump
The casting number is on the front of the body.
Date Codes and Where Are They?
Almost every mechanical part made for a Corvette has a date
code, either cast or stamped into it. These simply identify when the part was
made. To the factory, this date probably made sure that they didn't leave any
stock laying on the shelf too long, although if you have ever watched any
factory production line run, it is doubtful if anyone ever reads the dates. The
purpose of the date to Chevrolet was probably to ensure a means to track any
defects should they arise. If a part dated March 3 and one dated March 21 were
both defective, attention could be paid to those parts built between those
dates for other possible defects.
Today,
these are used to determine if the part is correct for that Corvette, as an
engine with a date code of D 16 5 (April 16, 1965) could not be correct for a
'63 Corvette as the engine was made after the car was made. Parts too early are
usually not correct either, as they would have been installed on an earlier
vehicle, such as a B 23 3 (Feb. 23, 1963) in a '67 Corvette. NCRS provides a
window of 6 months on date codes prior to the build date of the car. Obviously,
a part on a car could not have been made AFTER the car was made. (See Exceptions.) But given how new items were constantly loaded on shelves,
with existing items being shoved further back each time, a part could sit for
many months before being assembled on a car. Usually, the parts were used
within a few days or weeks but there are many documented original cars that
have parts several months old.
Be
sure to notice that some parts have both a casting and a stamped date code.
These can be several days apart. The stamped date code is when the part was
assembled and should be the one considered.
Engine Block
The date code on a SBC is typically on the bell housing flange
behind the distributor. On early big blocks, it was on the passenger side near
the pan rail, but later (1970) moved up to the same location as the SBC.
See Engine Block.
Usually
the date is given as a letter, a number and then a number, such as B 23 3 which
is for February 23, 1963. With any engine still having ignition shielding on,
you have a very hard time to see the date. A good flashlight and a wire brush
to clean any dirt are a must, even with the shielding removed.
Cylinder Heads
The date code is located on top under the rocker arms. You must
remove the valve covers to see them. Often lead deposits in old engines have
filled the numbers and letters so they are hard to read. Often the rockers are
in the way.
Intake Manifold
The small block usually has the date on the driver's side rear
runner. The date is typically below the casting part number. The firing order
(18436572) is usually cast on the front runner so do not confuse it with the
part number. Some big block intakes have the date cast under the intake so that
you must have the intake off the engine to see it.
Exhaust Manifolds
The casting numbers on the Ram horn manifolds are on the outside
near the 1-3 or 6-8 cylinders. On the big block manifolds, it is found low near
the outlet. The date codes on the Ram Horn manifolds are found on the opposite
end. On the big block manifolds, the date code is found on the back side.
Transmission
The Borg Warner transmission has a date cast into the main body
and tailshaft in the early T10s. Some later T10s ('70s) have it also. Usually
it is found on the passenger side. The
Rear end housing
The housing for the 1963 to 1979 differential has a casting date
on the drivers side. Again, this is the case date code. The assembly date is
stamped in the bottom of the case on the lip where the cover mates.
Alternator
The date code is stamped into the housing.
Water Pump
The water pump has a date code cast into the body in the front
but the pulley must be removed to see it usually.
Carburetor
Most of the earlier carburetors were built by Carter and had an
identifier tag attached to a cover bolt. This tag had the part number and date
code. On Holley carbs, the List Number is stamped on the drivers side air horn
in front along with either a 3 digit or 4 digit date code. The Rochester Quadra
Jet has a stamped number on the driver's side on a vertical pad.
Obviously, my biggest gripe with most restoration groups is
their inability to accept that there are exceptions. These were production cars
produced by a lot of guys who wanted to punch out and go home, not artists
creating an American legend. Most of what you see in restoration books and here
hold true, but exceptions do arise. If you see something that you have a gut
feeling is right, it may be. If the original owner claims it was never changed,
it probably hasn't. If a car salesman claims it, let the buyer beware.
The
purpose of NCRS, according to their books, is the "restoration,
preservation, and history of the Corvette", which they often overlook in
their judging manuals by deducting points for anything that is not
"right" without regards to production deviation. Some vehicles have
had original items removed because NCRS said they were wrong, only to discover
later they were correct. The history is usually obliterated when a car is
restored, as the significant part of many cars is what happened AFTER they left
the factory, not the assembly at the factory. (BTW, I am an NCRS member.)
Dates after the Body Date
Many forget that the body date is just that - the date of the
body. When A.O. Smith bodies were being shipped to
The CE is often defined as Chevrolet Engineering, Chevrolet
Engine, Customer Engine, and Crate Engine. I have never heard a definitive
answer. The CE block was a replacement engine that is accepted today as having been
only a warranty item. The engine pad carries a CE code instead of the
traditional codes on production engines. The VIN is usually not stamped in the
pad, but occasionally is in a very rough manner, often misaligned and irregular
depth, due to being hand stamped at the dealer, if at all. These are relatively
rare if in a Corvette within their warranty period as they would indicate a
Corvette that Chevrolet warranty work was performed on and the original engine
was destroyed. These are the only cases of Chevrolet intervening in the life of
a Corvette once it left the factory since engine replacement required Chevrolet
management authorization and most warranty work is simply handled by the
dealer.
A
few CE blocks have shown up in a few cars where the dealer appears to have
installed a CE as a non-warranty engine. These were outside the warranty
period. It may be that the CE was not a warranty only item but was used as any
dealer installed engine. However, as '60s Corvettes sold for around $2000 in
the early '70s, having the dealer install a $1000 or more engine was rather
foolish with the great availability of $100-$175 used engines and may have just
made a dealer installation a very rare occurrence.
Typically,
the stamp pad has a CExxxxxx stamped on it. Most reporting seem to have a 6
digit number. A few have a suffix similar to those on the production engines. I
do not have enough information to determine what the number meant and any
pattern to the suffixes, as to if they were long blocks or whole engines. Some
typical styles of stamping are:
- CE345321
- CE345321HF
- 422175 CE345321HF
Information
that has become known recently shows that these numbers have no meaning except
a sequential number. Thus, if a 300 hp 327, a 350 hp 327, a 385 hp 427, and
then a 195 hp 283 were to come down the line, they could be stamped CE12345,
CE12346, CE12347, and CE12348.
You can help if
you have a CE block by sending any information you may have. You could fill out
the survey at http://www.geocities.com/MotorCity/Downs/3000/ceblock.html.
Reference Material
No matter what I put in here, you cannot beat what has already
been written and continually updated. Some excellent references you need to get
are:
- 1953 - 1972 Corvette
Specification Guide, by National Corvette Restorers Society. This has been
updated now and there are two books: one for 1953 to 1967 Corvettes and
the other for 1968 to 1982 Corvettes. These are very helpful.
- Catalog of Chevy V-8
Engine Casting Numbers 1953-1993 and stamped numbers, by Cars & Parts
Magazine
- Noland Adams' two
books
- The Complete
Corvette Restoration & Technical Guide Vol. I for 1953 through 1962
- The Complete
Corvette Restoration & Technical Guide Vol. II for 1963 though 1967
- From M.F. Dobbins,
Inc.,
- Vette Vues Fact
Book of the 1963-1967 Sting Ray (9th Edition)
- Vette Vues Fact
Book of the 1968-1972 Stingray (4th Edition)
- Vette Vues Fact
Book of the 1973-1977 Stingray
- NCRS Judging Manual
for the year in question
- Corvette Factory
Assembly Manuals for the year in question
- The Genuine Corvette
Black Book, by Michael Antonick