1968 Corvette Identification Numbers

Vehicle Identification Number information and other identification numbers for the 1968 Corvette including engine block, head id, casting numbers and more.

VIN Tag Information
194378S400001 - 194378S428566 (coupe)
194678S400001 - 194678S428566 (convertible)
Digit Definition
1st Division:  1 = Chevrolet
2nd / 3rd Series:  94 = Corvette
4th/5th Body Style:  37 = 2-door coupe, 67 = 2-door convertible
6th Model Year:  8 = 1968
7th Assembly Plant:  S = St. Louis, MO.
Last 6 digits Production Number starting with 400001 - 428566

Engine Suffix ID Numbers
HE: 327ci, 300hp (manual transmission)
HO: 327ci, 300hp (automatic transmission)
HP: 327ci, 350hp (air conditioning, manual transmission, power steering)
HT: 327ci, 350hp (manual transmission)
IL: 427ci, 390hp (manual transmission)
IM: 427ci, 400hp (manual transmission)
IO: 427ci, 400hp (automatic transmission)
IQ: 427ci, 390hp (automatic transmission)
IR: 427ci, 435hp (manual transmission)
IT: 427ci, 430hp (L88) (aluminum heads, manual transmission)
IU: 427ci, 435hp (aluminum heads, manual transmission)

Block ID Numbers
3914678: 327ci, 300hp, 350hp
3916321: 427ci, 390hp, 400hp, 430hp, 435hp
3935439: 427ci, 430hp, 435hp

Head ID Numbers
3917215: 427ci, 390hp, 400hp
3917291: 327ci, 300hp, 350hp
3917292: 327ci, 350hp
3919840: 427ci, 435hp (iron heads)
3919842: 427ci, 430hp, 435hp (aluminum heads)

Cylinder Head Casting Number:
The cylinder head casting number is usually found on top of the cylinder head in between two valves and the rocker arm studs.

Cylinder Head Casting Date:
The cylinder head casting date is usually found adjacent to the cylinder head casting number. The casting date code is an alphanumeric sequenced number. The first digit is usually a letter which specifies the month that the block was cast. Some casting dates have been found with all digits being numbers, the first of which corresponds to the month.

Cylinder Head Casting Number Month Codes (1st Digit)
A - January E - May I - September
B - February F - June J - October
C - March G - July K - November
D - April H - August L - December

Two main plants were casting Chevrolet engine parts during 1968: Flint, Michigan and Tonawanda, New York.

Example:  Flint Cylinder Head Casting Number - D 19 9

  • D:  Month = April
  • 19:  Casting Day = 19th
  • 9:  Casting Year = 1959

Example:  Tonawanda Cylinder Head Casting Number - D 19 59

  • D:  Month = April
  • 19:  Casting Day = 19th
  • 59:  Casting Year = 1959

Carburetor ID Numbers
Rochester Q-jet #7028207: 327ci, 300hp (manual transmission)
Rochester Q-jet #7028208: 327ci, 300hp (automatic transmission)
Rochester Q-jet #7028209: 427ci, 390hp (manual transmission)
Rochester Q-jet #7028216: 427ci, 390hp (automatic transmission)
Rochester Q-jet #7028219: 327ci, 350hp (manual transmission)
Holley R3659A #3902353: 427ci, 400hp, 435hp (front carburetor, rear carburetor)
Holley R4054A #3925519: 427ci, 430hp (L88)
Holley R4055A #3925517: 427ci, 400hp (center carburetor, manual transmission), 435hp (center carburetor, first design)
Holley R4055-1A #3940929: 427ci, 400hp (center carburetor, manual transmission), 435hp (center carburetor, second design)
Holley R4056A #3902516: 427ci, 400hp (automatic transmission, center carburetor, first design)
Holley R4056-1A #3940930: 427ci, 400hp (automatic transmission, center carburetor, second design)

Distributor ID Numbers
1111194: 327ci, 300hp
1111293: 427ci, 390hp, 400hp
1111294: 427ci, 390hp, 400hp (transistor ignition)
1111295: 427ci, 430hp (transistor ignition)
1111296: 427ci, 435hp (transistor ignition)
1111438: 327ci, 350hp
1111441: 327ci, 350hp (first design, transistor ignition)
1111475: 327ci, 350hp (second design, transistor ignition)

Alternator ID Numbers
1100693: 300hp, 350hp, 390hp, 400hp
1100696: 350hp, 390hp, 400hp, 430hp, 435hp (transistor ignition)
1100750: All engines equipped witih air conditioning.

Transmission ID Numbers
S Saginaw 3-Speed
P Muncie 4-Speed
K Turbo Hydra-Matic 400, Corvette 327 Engines
L Turbo Hydra-Matic 400, Corvette 427 Engines

  • Seven inch, silver painted wheels were unique to the 1968 model year..
  • Unique to the 1968 model year was a special door opening system that consisted of a separate release button and a spring-loaded finger plate.
  • The side gills on the 1968 Corvette did not come with the chrome inserts which were an option on the 1969 model year.
  • This was the first year for a new cabin ventilation system called "Astro-Ventilation", windshield wipers that were hidden under a vacuum-actuated door panel at the base of the windshield, and a special fiber-optic light monitoring system.
Click for larger image Exterior Emblems:
  • Model Years:  1968 - 1969
  • Description:
    • This hood with the 427 emblem was only used with the L36, L68 and L71 427ci engine options for 1968 and 1969.
Click on picture for enlarged image. Trim Tag:
  • Description:  This contains factory ordered color and trim option codes.
  • Location:  The Trim Tag is located on the driver's door hinge pillar.
Click on picture for enlarged image. Protect-O-Plate:
  • Description:  The Protect-O-Plate — a thin metal plate or plastic card issued to car owners starting in the '60s to help dealers track warranty work — has become a "buzz word" for collectors wishing to document the authenticity of their vehicles. Apparently the term "Protect-O-Plate" was used solely by General Motors.
  • Location:  NA