understanding-numbers-codes-feature

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Nearly all of the major parts found in 1968-1982 Corvettes contain a part number and date code. Developing a better understanding of these numbers and codes and how they relate to one another will enhance your enjoyment of the hobby.

The logical starting point for the analysis of part numbers and date codes on any Corvette is the car’s vehicle identification number (VIN). For all vintage Corvettes the first several characters of the VIN indicate the model year, body style, and assembly plant and the latter characters are the sequential number of each particular vehicle. Beginning in 1972 the fifth character in the VIN indicated which engine the car originally came with. The VIN was stamped into a rectangular metal plate that was riveted to the windshield support frame at the driver side base of the windshield on all 1969-82 Corvettes. Every car’s VIN was also stamped into the chassis in at least one place. For most C3s it was stamped into the chassis on top of the side rail on the driver side in both the area beneath the door and the area above the rear wheel. For all C3s the latter half of the VIN, often called the VIN derivative, was stamped into the car’s original engine block. This stamping was on a flat pad just above the water pump mount area on the passenger side. It also was stamped into the car’s original transmission case.

One way to help verify whether a specific engine or transmission is original to a given car is to compare the car’s VIN to the VIN derivative in the stamping on the block or case. A stamping that does not match the car’s VIN almost certainly means the engine or transmission is not original to that car. A stamping that does match the latter half of the VIN usually means the assemblies are original but even matching numbers does not guarantee this because of a practice commonly referred to as re-stamping. In order to make a non-original engine or transmission appear like the original some people will stamp the correct numbers into the parts. They accomplish this by either machining the existing numbers off or starting with a block or case that never had numbers stamped in to begin with. Evaluating the originality of engine and transmission stampings is a science unto itself and if matching numbers are important to you it is best to enlist the services of an expert.

In addition to the VIN derivative, original Corvette engines also have what’s called an assembly sequence. This is stamped into the block adjacent to the VIN sequence. The assembly sequence indicates the engine’s manufacturing plant, date of assembly, horsepower and application. As with the VIN derivative stamping, the engine assembly stamping can go a long way in helping you determine whether a given engine is original to a particular car. But as with the VIN stamping, engine assembly stampings can be “re-stamped” so just having the correct letters and numbers does not guarantee that the engine is in fact original.

Production records for all Corvettes built in the Bowling Green assembly plant still exist but precise assembly dates for C3s assembled in the St. Louis plant are not known. You can however, determine their approximate assembly day with a fair degree of accuracy. For nearly all months of production the final serial number car assembled on the last working day of the month is known and therefore the total production for each month is known. Using this information and your car’s VIN you can determine which day your car was built. For example, if the final VIN for February was 11,000 and the final VIN for March was 12,600 and your car is VIN 11,786, then you know your car was made in March. You also know they made 1,600 cars in March. Divide that number by the total number of working days in the month and you have approximately how many cars were produced each working day and the VIN range for each of those days. Plug your VIN in and you know which day your car was made – give or take a day or two for slight irregularities in daily output.

Once you have the assembly date for you car in-hand you can evaluate the correctness of all of its dated components. All component manufacturing dates have to precede the final assembly of the car and the generally accepted rule of thumb is that they should not precede it by more than 6 months. For example, if your car was assembled on May 8th all of its dated components, such as the alternator, radiator, wheels, engine, differential, transmission and body glass, will be dated earlier than May 8th but no later than about November 8th of the previous year if in fact those components are original. Reading manufacturing dates on most components is pretty straightforward. Typically, a single number represents the year, a letter represents the month with A being January, B being February, and so on, and one or two additional numbers represent the day. For example, an alternator dated 9B21 was made February 9, 1969. In addition to reading date codes it is also important to evaluate the part numbers on major components. All major cast parts, including the engine block, cylinder heads, intake and exhaust manifolds, and transmission case, have a casting number. Most other significant parts, such as the radiator, alternator, starter, distributor, carburetor and wheels, have either a stamped-in part number or a part number tag.

Upon reading this restoration tip brought to you by Zip Corvette, which can also be found in our free Corvette Parts Restoration Catalogs, you may have many questions about the numbers and codes found on your Corvette. If that is the case our Corvette Number & Paint Guides are exactly what you are in need of. Each guide incorporates materials from the GM archives that has been compiled to offer the most authoritative reference available for finding, decoding and verifying the correct part and casting numbers of every engine and drivetrain component for 1955-1982 Corvettes and other Chevrolet models. Each book is loaded with photographs, blueprints, technical bulletins and build sheets all of which will help you easily determine exactly what your Corvette is/was equipped with.

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76 thoughts on “Corvette Restoration Tip: Understanding Numbers & Codes

  1. I currently own a 1971 Corvette convertible Stingray.The VIN# is 194671S113302. I would like to know how could I get a build sheet for my car specifically. I purchased the car 12 years ago and I believe the fuel tank was replaced. I think most build sheets were attached above the original tank.

    Secondly I have both a soft and hard top for my car.The car is arctic white with red interior. My hard top is white and black not red. Is this correct for my hard top?

    Thank you.

  2. Unfortunately bill sheet records are not available prior to 1981 when the Corvette Assembly plant moved to Bowling Green. Hopefully with the expansion of the Corvette Museum and access to Chevrolet archives, bill sheets will one day be available for your Corvette. Often times tanks were replaced, bill sheets lost and documentation for your Corvette unavailable. Often times another bill sheet was stuffed into your Corvette during assembly. These sheets can sometimes be found either behind the door panel, behind the quarter panels or rear carpet, or even stuffed into a seat cushion.

    Hardtop headliners would have matched the interior color of your Corvette. Possibly the headliner was replaced with another original prior to reproduction availability. The headliners commonly get destroyed, especially on the lower sections as tops are installed and removed from Corvettes.

  3. I am thinking of purchasing a 1969 Corvette with 69,000 miles. I do not know if the engine is original to the car. The VIN is 194679S706262 and the engine suffix is vo9i6wa, how do I tell if it is or not? If it is not is it the end of the world? I feel I am getting a great deal and am probably getting the car for less than about $4,000. The car has a brand new interior and the body is straight. The Corvette has been sitting for about 12 years and the engine has about 100 miles on it. The guy selling it does not know if the engine was rebuilt or if it is a new 350.

    Thanks,

    Dave

  4. Dave,
    According to our Chevy By The Numbers book that engine is not original to the car. With that said I could not find that suffix (vo9i6wa) listed for any 1955-1982 Corvette Engines.

    If the engine is incorrect then obviously it will not pass judging standards. However, if you are not going to have the Corvette judged and are just looking for a nice driver it sounds like you may have found a nice ride.

  5. I currently have a 1979 Corvette with vin # 1z8789s402112. What engine should be in it?
    Jesse

  6. Jim,
    The differential code is stamped on the bottom of the differential carrier housing just forward of the rear end cover. The two letter prefix designates the gear ratio and any other specific information. Code AA=Posi 3.55:1, AB=Posi 3.70:1, AC=Posi 4.11:1, AW=Posi 3.08:1, AX=3.36:1, LR=Posi 3.36:1.

  7. I have a 1972 Corvette with vin# 1z37w2s516141. Can you tell me what each number means?

  8. Bo,
    I can tell you that the “W” means the Corvette originally had a 454 big block engine. The “2″ means it is a coupe and the last 6 digits represent the sequence number assigned to that Corvette when it was built.

  9. The engine # is 3999289. Is that the orginal Corvette Engine that came from factory?

  10. Johnny,
    Actually at one time that was a very popular modification. I do not know if all of the necessary parts are available but yes a 454 engine will fit into a 1984 Corvette.

  11. I am looking to purchase a 1968 Corvette with VIN# 194678S400084. The Corvette has a mid 70s 350 Corvette engine. How do I find out what the original engine was?

  12. Clint,
    There really is no way to tell what engine was originally in that Corvette. Even if the Corvette was here in our shop we still could not guarantee that we would be able to tell you. If the Corvette has had multiple owners, which many have, the odds of figuring out what the original engine was are even smaller. I wish we could help you more but unfortunatlly this is a problem many people have to deal with when restoring pre-1972 Corvettes.

  13. This is stamped on my Corvette’s rear end housing: OH 115 W8E1. I know OH is 78-79 3.55 but what is the rest?

  14. Thomas,
    Like you said the OH designates that the Corvette’s rear end gear ratio is 3.55:1. The 115 designates that it was built on the 115th day of the year. The W is the plant code and means that it was built in Warren, Michigan. According to our information a traditional Corvette rear axle would read like this: OH C 218 1. The OH = axle prefix, C = Assembly Plant, 218 = day of year, 1 = shift.

  15. I recently purchased a 1955 Chevy Belair, with an early generation LT1 Corvette engine in it. I was trying to find out more about the engine. The casting # is 3970010 and the stamped # on the front right is 101100741k0814cnv. Does anyone have any information on this?

  16. Looking at buying a 1968 Corvette with vin #194378S413340. Numbers on the engine are V0509HE and also 7119708. Is this the original engine for this car? Also on the trim plate the Numbrs are 402 & 983, what can you tell me about these numbers? Also would you be able to tell me what options were on this Corvette when it was built looking at the vin number?

  17. Jeff,
    The 1968 Corvette you are looking at buying was originally British Green with black leather interior. The engine code V0509HE designates the engine was assembled on May 9th and that it is a 327/300 horsepower motor with manual transmission. The other engine number provided does not seem to be a correct code for any 1968 Corvette.

  18. My Corvette’s speedometer reflects a 10 mile difference @ 60mph; I am actually doing 70. Does anyone know if this is the speedometer or the transmission speedometer gear that is not working properly?

  19. The VIN number on my 1996 Corvette LT-4 is 1G1yy3250T5113730. Can anyone tell me anything at all about it? I don’t have a build sheet with the car and have no idea what is original and what is not. Nor do I know what options came on the Corvette. I’d like to thank anybody that can help me in advance.

  20. How do I figure out what gear to purchase to make it correct? I have a 454 with a 4 speed. Not sure about the gear ratio in the rear end though.

  21. Jose,
    You can’t figure out what gear to purchase without trial and error. The rear gear ratio is the most important number in factoring which gear to purchase.

  22. I have a set of side windows with frames for a 1958 Corvette. These are original equipment, not reproductions. What are these worth these days? I understand they fit 1957-1962 Corvettes.

  23. Do you know how or where I could locate a numbers matching engine for a 1969 Corvette, VIN #194379S706676? It should be a 350ci/350hp for a 4-speed manual transmission with A/C.

  24. Don,
    No, there is not a “replacement” matching numbers engine for your Corvette. You could look for a correct casting number block, but matching numbers also means it has your VIN stamped in the pad of the engine. Unless you find your original engine I’m afraid all else would be a forgery.

  25. My husband has a 1962 Corvette. I want to get a part for him as a present. I have the Vin#: 20867S111009 and I know it was assembled in St. Louis but I would like to know what month it was made.

  26. I have a 1969 Corvette with an L88 hood, the passenger side pops open with the hood latch but the drivers side will not. Is there any way to get it to open without breaking the hood or latch?

  27. Steven,
    Yes, but you are going to have to remove the wiper door grill. In your Corvette’s wiper tray there is a plastic grommet, pop it out and you can use a screwdriver to pop your Corvette’s hood latch. The reason the passenger side is popping and the driver side is not is because the latch on the hood is not adjusted properly. Use some white grease to locate where it is on the latch and adjust it so the catch will pull back on it to clear the pin.

  28. I recently inherited a 1978, 25th Anniversary Edition Corvette, with VIN 1z8748s433159. Can you tell me anything about this engine? Place of manufacture, etc. Thank you.

  29. I just bought a 1973 Corvette with manual brakes. Is it hard to convert to power brakes and was it common to put manual brakes on a 1973 Corvette?

  30. I have a 1982 Corvette and the thermostat housing bolt is broken. I found an intake from a 1984 Corvette on eBay for $130. Would this be an exact match?

  31. The casting number on my 1982 Corvette is14031372 and the one on eBay for the 84 is 14057017…Why do they have different casting numbers if they are the same? I just want to make sure everything bolts up correctly.

  32. George,
    I do not know why they had a different casting number. I have had many of them side by side and everything looks the same, however I have never taken a 1984 Corvette intake and installed it on a 1982. I also have not had one in at least 10 years.

  33. Barry,
    It depends on where it comes from and what is damaged on it before you start. You can’t get a new 1973 Corvette 4 speed transmission so purchasing a rebuilt transmission or rebuilding your own is the only option. You can pick up a used transmission for around $500 if you are not looking for specific dates. You will likely pay at least that to have it rebuilt.

  34. George,
    I have a customer that has a 1969 Corvette that has a 427 in it and it is not a matching numbers car. How do I tell if it came with a small block or a big block? Is there any differences in the suspension or raidiator?

  35. I have a 1982 Corvette and need a rear drive shaft. I have purchased two and they are to long. Can you tell me the exact length? Transmission is 700r4.

  36. There is no real solid answer to this. Just as someone could have installed that 427 in place of a 350 all of the other components could have had the same thing done. You can start by looking at the radiator, if the Corvette is a 4 speed w/o air a SB had a small 19” radiator, however if it was an at or a/c car it would have had the bigger radiator. You can look to see if it has the rear sway bar, the big block Corvettes had rear sway bars. You can look at the tachometer to determine what horsepower the car was and that alone could determine. The issue is most of the parts were the same but a select few, and those could easily be changed. It was not until 1971 that the engine became a digit in the VIN number.

  37. Yes and No, it will fit but you will not be able to use any of the ignition shielding and your Tachometer will not work unless you purchase a tach drive HEI. We suggest an Electronic Conversion Kit for your factory distributor, that way it will look stock but it would be an electronic unit.

  38. I have a 1966 big block 427-425 HP Corvette. The engine stamp begins with the letters TO which indicates that the engine was not built in Flint. I was told that this means it is not a Corvette engine since they were all built in Flint. It is a Top Flight car with the original engine. Is this true?

  39. @Jimmy C. Phillips
    The first number (1) is the country of origin. The second (G) is General Motors, the third (1) is make chevrolet, the fourth (yy) is corvette, fifth is (3) for convertible, sixth is (2) for automatic trans, seventh is (5) for the LT4 engine, the eighth is (O) varies, the ninth is (T) is the year manufactured 1996, the tenth is (5) Bowling Green Kentucky, and the final sequence of numbers is the production number beginning with 100001. Hope this answers part of your question.

  40. I have a 1979 Corvette. I was told the engine was the original. VIN#1Z8789S424955 Engine is stamped ZAJ. Is the engine a 350-195hp?

  41. Nick,
    The engine plant abbreviations, obviously differed depending on the letter designation given. “F” indicated Flint, Michigan. “T” indicates: Tonowanda, New York. Sounds like you do have a Corvette engine!

  42. Alan,
    The VIN# clearly marks this Corvette as a year 1979. “ZAJ” indicates that this is a 350-195hp, which also states it as an Automatic transmission with California Emissions!

  43. I have a 1967 Corvette, Vin number 194677S103366. The engine stamp is E276. How do I find if the numbers match?

  44. I came across a 1969 Corvette with no engine and trans but in the interior of this Corvette was the shifter plate which read 427 cu in L88. How can I tell if that what this Corvette came with? It’s a Barn find that’s been sitting for the last 25 years.

  45. John:
    The only way to verify that it may be a real L88 Corvette is to check to see if the Corvette has an build sheet still mounted to the top of the gas tank. This will match up the build options (including engine RPO) and the serial or VIN number of that particular Corvette. Otherwise, the Corvette is just a no engine 1969 Corvette. Adequate documentation is required for the Corvette to have significant value.
    Another option to consider: If you have already purchased this Corvette, you can pay to have an expert come out and go over the car. They should be able to tell if it’s a real L88. There were options that went with them and a certain time they were produced and an expert will be able to decode this by vin and body tag. I’m not sure of the costs involved, but it would be well worth the cost if they confirm it is a real Corvette. I would call Kevin from Corvette Repair, his number is 516-568-1959.

  46. Linda:
    “Numbers match” refers to whether the Corvette Engine is the original engine that came in it when it was delivered to the original purchaser. To verify the original engine – the last 6 digits of the VIN number would be stamped into the flat pad located on the front RH side of the engine. This area also includes the date when the engine was assembled AND the engine code which is specific to the horsepower/transmission combination. This area is usually “decked” during a rebuild, so often, the engine codes/vin number is removed and you will find engines that are restamped with the numbers. Many times, this practice is done to fraudulently create a supposed original engine. To verify if the engine is original:
    1. Verify the engine block is the correct casting # – located on back LH side
    2. Verify the engine block was cast at the appropriate time – date on back of LH side
    3. Verify VIN number stamping in front RH side
    4. Verify date of engine assembly based on build date of Corvette
    5. Verify that NONE of these number have been tampered with or restamped

  47. I have a 67 Vette convertible I can not find out what the style # means. It is a K27 the Vin is 194677S12189. The paint is 986AA and the Body is 99070. I also have a # on the tag by glove box that is 67 467. Can anyone help me identify what type of engine build I may have had?

  48. We purchased a motor that was totally rebuilt and the guy said it was an original Corvette motor. From the numbers stamped on the block, is it possible to verify if what he said was true? The motor is a 350.
    Thanks!!

  49. Jake:
    The only means for determining the original engine build for your Corvette would be to have original paperwork (tank sticker or build sheet) or confirm your Corvette has the original engine (vin # on body matches vin # on pad located in front of the RH cylinder head) and then decipher the engine code stamped on the engine. There is no engine information available through the VIN # only or the body tag you have provided.
    The body tag info which you found on the glove box provides info from the AO Smith or St. Louis Body assembly plant. K27 identifies your body as being built in June 27th of 1967 – which is at the end of the month. Your Corvette was also built very late in the month of June 1967 based on the VIN #. The 986AA refers to a silver exterior color and the 67 467 refers to a convertible body. We think your body # is really S9070 which would refer to the St. Louis body plant and the 9070th body built during that year.
    We hope this helps. All of this information can be found in the Corvette by the Numbers book which we recommend to everyone who wants to understand the markings, numbers and identifiers of their Corvette.

  50. Debbie -
    The short answer is MAYBE.
    First, GM used the same block in Corvettes that they did in other cars, so we need you to provide the casting number on the back drivers side. Also, the front stamp pad on the passenger side should have numbers stamped in it. This will tell us when the engine was assembled and what it went into, plus what HP it was. If the block has been decked then there will be no way to know for sure.

  51. Hello. I just bought a ’72 Stingray. I’m pretty sure it doesn’t have the original motor. I looked at the engine and found these numbers… 11W277533 V0511CGA….I cannot find out the year, size and where it was made. Can you help me identify my engine, so I’ll know how to repair it? The person I bought it from has not been helpful at all.
    Please e-mail me ASAP, I’ve had it for 3 weeks now and I want to drive this sexy thing!! :)

  52. Shelli:
    These numbers look like date codes, not block numbers. We will need to check another number that is actually cast onto the block – located on the upper rear of the driver’s side of the block near the flywheel attachment. This number should be about 7 digits; and for 1972, and would begin with 397. Otherwise, we could look at some numbers stamped into a pad just forward of the head on the passenger’s side of the engine. If you could provide any of these sets of numbers; then we may be able to help with identifying this motor.

  53. I have 5 sets of 1968 – 1973 “corvette” o.e.m. lettering. How do I tell if they are real?

  54. John:
    The original letters from GM were very rough. Casting lines in had a lot of slag on them. Reproduction are nicer and cleaner due to the new tooling. Hope this helps!

  55. The engine block number on my 59 Corvette reads F 72 ICU….what does this indicate?

  56. Larry:
    The number should read F 7 21 CU
    F-indicating that the car was made at the Flint Michigan plant
    7-indicating it was made during the 7th month( July)
    21–indicating 21st day
    CU-indicating the engine size in this case ( 270 hp, manual transmission, Dual 4BBL, and had a hi-lift camshaft in car)

    You can find all this information in Corvettes By The Numbers, an authoritative reference book for finding, decoding and verifying the correct part and casting numbers of every engine and drivetrain component for ’55-82 Corvettes.

  57. Hi there
    I hope you can help me to decode what these numbers tell me.
    VIN 194671S107158.3968512 (Im not sure what the numbers after the dot are but think its the Block Cast # from what I’ve read)
    Engine T052 6LE19J301735
    Thanks

  58. Cindy:
    The Vin indicates that this Corvette is a 1971 Convertible; and it was built in January of ’71. The number after the dot should read: 3963512; and, if so, it is a 454ci 365 or 425 hp. The other numbers, T052 etc don’t make sense as they stand. Hope that helps.

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