Small/Big Block Chevy Engine Code Stamping Numbers: Explained and Decoded

Small/big block Chevy Engine code stamping numbers include engine ID code, engine VIN, block casting number, and block date code. 

Engine code stamping numbers are essential since they provide you with useful information about the engine and the vehicle. They help in identifying the assembly factory of the engine block you have. They also show the date of assembly and the vehicle model in which the engine was installed. 

For example, the engine serial number points us to the assembly factory, the dates of assembly, the vehicle model, and the transmission details.

Read more to find out more about the stamping numbers. 

Chevy Small/Big Block Engine Code Stamping Numbers 

Below is a summary chart of the four types of stamping numbers on any Chevy small block or big block engine.

Engine Code Stamping NumbersLocationDecodingExample
Engine Serial Number (Engine ID code)- At the front passenger side of the block, next to cylinder #2; or
- On the flat block just above the timing cover (in some truck or marine blocks)
1st letter = assembly factory;
2nd and 3rd digits = month of the assembly;
4th and 5th digits = day of the assembly;
Last 2 or 3 digits = Engine Suffix code
T0525ED means
T = Tonawanda
05 = May
25 = 25th 
ED = Chevelle, Manual Transmission
Engine VIN- At the front passenger side of the block, next to cylinder #2; or - On the flat block just above the timing cover (in some truck or marine blocks)1st Number = GM Division
2nd Number = Production year.
3rd Letter = The assembly plant.
Last 6 Digits = Equal the last 6 digits of the vehicle’s VIN.
17N123456 means
1 = Chevrolet
7 = 1967
N = Norwood, Ohio
012345 = The last six digits of the vehicle's VIN
Block casting number- At the back ledge of the block behind the driver-side cylinder head, next to cylinder #7; or
- On the passenger side ledge, next to cylinder #8 (on some later production blocks)
Designating:
- The displacement;
- The year of production; 
- 2 or 4 bolt main;
- Vehicle application.
14316379 means
CID: 350, 
Years: 68-88
Notes: Car & Truck 2-bolt Passenger stick 1-piece seal
Block Date Code- At the back ledge of the block behind the passenger side cylinder head, next to cylinder #8; or
- On the passenger side of the block near the freeze plug (in some earlier production blocks from the 60s); or
- On the driver side ledge (on some later blocks)
1st digit = month;
The next 1 or 2 digits = date
The last number = year
Example 1: A72 means
A = January
7 = 7th
2 = 1962, 1972, 1982, or 1992
Example 2: C106 means
C = March
10 = 10th
7 = 1966, 1976, 1986, or 1996
Note: For the year, more info is needed as the 7 can mean 67, 77, 87, or 97.

Chevy Small/Big Block Engine Serial Number

What Is Engine Serial Number?

Chevy Engine Serial Number
A Chevy engine serial number is a unique ESN used to identify every Chevy vehicle.
Credit: flickr.com

A Chevy engine serial number is a unique ESN used to identify every Chevy vehicle. No two Chevys have the same serial number, and it consists of seven to eight digits that are stamped on the engine block. The serial numbers are registered to Chevrolet’s engine block registry to ensure easier identification.

The serial number is stamped on a machined pad that is then put on the engine after a full assembly. It contains information about the vehicle’s assembly, power output figures, the make & model of the Chevy vehicle, and the engine displacement. 

The engine serial number in big and small Chevy engines is denoted by seven digits, each symbolizing a specific detail. Below is the meaning of each of the letters and numbers in the engine serial number:

  • 1st letter = assembly factory
  • 2nd and 3rd digits = month of the assembly
  • 4th and 5th digits = day of the assembly
  • Last 2 or 3 digits = Engine Suffix code

The first five digits are called the prefix and contain the details about the engine assembly factory, the month in which the assembly was made, and the specific day of the assembly. 

The last two to three digits indicate the engine suffix code used to denote the vehicle model and the transmission details. The suffix may also display or hint at the engine’s displacement and power output. 

The assembly plants include: 

  • F for Flint, 
  • H for Hydramatic, 
  • K for St, Catherines, Ontario, 
  • M for General Motors in Mexico, 
  • T for Tonawanda, 
  • S for Saginaw Service, and 
  • V for Flint. 

For example, the engine serial number V1015CKX is decoded as: 

  • V– the production assembly factory in Flint. 
  • 10 – denotes the month of assembly, which is October. 
  • 15 – denotes the day of the assembly, which is the 15th. 
  • CKX – indicates the vehicle it belongs to, which is either a 1973 Camaro, 1972 Corvette, or 1976 Corvette, all with 350 cubic inch displacements, and power output between 145 hp and 200 hp. 

Another example is the serial number T0525ED:

  • T = Tonawanda
  • 05 = May
  • 25 = 25th 
  • ED = Chevelle, Manual Transmission

Read more: SBC BBC V6 Chevy Engines Specs and Sizes

Engine Serial Number Location

The engine serial number is located at the front passenger side of the block, right next to cylinder #2. In other vehicles, you may find the serial number located on the flat block just above the timing cover (in some truck or marine blocks.)

Besides, location varies between Chevy vehicles due to configurations and model numbers. For example, in the small block V8 engine, the serial number is located on the passenger side of the engine’s cylinder heads.

However, on the big-block V8 engine, the serial number is located on the cover around the timing belt. Keep in mind some small block, and big block engines have the number stamped in the same place. 

Chevy Engine Serial Number Location
The engine serial number is located at the front passenger side of the block, right next to cylinder #2.
Credit: chevyasylum.com

GM/Chevy Engine Serial Numbers Lookup

SBC/BBC Engine VIN

What Is Engine VIN?

The Chevy big/small block engine VIN is a combination of digits that indicate the type of vehicle the engine is installed in and the model year and the assembly plant. The engine VIN also contains six digits that are used to denote the last six digits of the vehicle’s VIN. 

It is essential to distinguish the engine VIN and the vehicle’s VIN since they are different numbers. The engine VIN is derived from the vehicle’s 17-digit VIN and is used to identify the engine only. On the other hand, the vehicle VIN is no longer used to determine the body style, the engine type, the security code, the platform code, and further details. 

  • 1st Number = GM Division
  • 2nd Number = Production year.
  • 3rd Letter = The assembly plant.
  • Last 6 Digits = Equal the last six digits of the vehicle’s VIN.

For example, the Chevy engine VIN 17N012345 means;

  • 1 = Chevrolet
  • 7 = 1967
  • N = Norwood, Ohio
  • 012345 = The last six digits of the vehicle’s VIN

Another example of the engine VIN is 13N100001 which means: 

  • 1 = Chevrolet
  • 3 = 1973
  • N = Norwood
  • 100001 = the last six digits of the Chevy 1973 vehicle’s VIN. 

The assembly plant information is denoted with the third letter, which can be a number in some vehicle models. They mandated this format in 1972 after abolishing a longer form that used letters like NOR to show Norwood instead of the current N for Norwood. Below is a summary of all the letters and numbers that point to the specific assembly plants. 

A = LakewoodL = Van NuysW = Willow Run4 = Scarborough
A = Atlanta GA
B = BaltimoreM = LansingX = Fairfax5 = Bowling Green
C = Lansing (B)N = NorwoodY = Wilmington5 = London
C = Southgate CA.
D = Doraville GAP = Pontiac (Pontiac)Z = Fremont6 = Oklahoma City
E = LindenQ = Detriot1 = Wentzville7 = Lordstown
F = Flint (Chevy)R = Arlington1 = Oshawa #28 = Shreveport
G = FraminghamS = St. Louis2 = Moraine (T&B)8 = Fujisawa (Japan) Luv
H = Flint (Buick)S = Ramos Arizpe2 = St. Therese9 = Detroit (Cadillac)
J = JanesvilleT = Tarrytown3 = Detroit (T&B)9 = Oshawa #1
K = Kansas CityU = Hamtramck3 = St. Eustache0 GM Truck Pontiac
K - KosaiU = Lordstown OH.
K = LeedsV= Pontiac (GMC)4 = Orion

Engine VIN Location

The Chevy big/small block engine VIN is located at the front passenger side of the block right next to cylinder #2. You may also find it located on the flat block just above the timing cover (in some truck or marine blocks). For example, in small block engines made between 1968 and 1969, the engine VIN was stamped next to the engine ID code or below it. 

Read more: GM/Chevy Engine Serial Number Lookup

Small/Big Block Casting Number

What Is Block Casting Number?

The small/big block engine casting numbers are used to identify the engine block by denoting the casting number, the year of production, and the CID. 

The casting number of the Chevy engine blocks shows various details of the engine block that include: 

  • The displacement
  • The year of production
  • 2 or 4 bolt main
  • Vehicle application

It is important to note that Car & Truck 2-bolt Passenger stick a 1-piece seal.

For example, the Chevy engine casting number 14316379 means;

  • CID: 350, 
  • Years: 68-88

Block Casting Number Location

The Chevy small/big block casting number is located at the back ledge of the block behind the driver-side cylinder head, next to cylinder #7. 

In some vehicles, the casting number is situated on the passenger side ledge, next to cylinder #8 (on some later production blocks)

Chevy Big/Small Block Casting Numbers Lookup

Chevy SBC and BBC engine casting number.

Read more: SBC Head Casting Numbers: Full List & Lookup

Small/Big Block Date Code

What Is Block Date Code?

Chevy small/big block date codes are either alphanumeric or numeric. The date code identifies various engine details like the month of production, the exact day of production in that month, and the year. 

The Chevy engine date codes are denoted as follows: 

  • 1st digit = month;
  • The next 1 or 2 digits = date
  • The last number = year

An example of such a date code is the A72 which means;

  • A = January
  • 7 = 7th
  • 2 = 1962, 1972, 1982, or 1992

Another example is the C106 which means;

  • C = March
  • 10 = 10th
  • 7 = 1966, 1976, 1986, or 1996

One crucial piece of information to remember about the year is that more information is needed from the other numbers (serial and VIN). This is because numbers like “7” can mean different years like 67, 77, 87, or 97.

The digit denoting the month is usually a letter between A and L but can include numerical numbers in some instances, with 1 indicating January and 12 December.

LetterMonth
AJanuary
BFebruary
CMarch
DApril
EMay
FJune
GJuly
HAugust
ISeptember
JOctober
KNovember
LDecember

Block Date Code Location

The Chevy small/big block engine date codes are located at the back ledge of the block behind the passenger side cylinder head, next to cylinder #8. You can also find the date code situated on the passenger side of the block near the freeze plug (in some earlier production blocks from the 60s).

Some other Chevy models will include the date code on the drive side ledge, especially on the recently manufactured blocks. 

Summary

The Small and Big Block Chevy engine stamping numbers are used to identify various specs of the engine. Please keep a look at their locations and denotation since it is essential for anyone looking to perform engine swaps and design modifications. 

Read more: Small Block Vs. Big Block: Which Chevy Engine Style Is Better?

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