How to Identify a Serial Number on a Chevy Big Block Engine

by Richard Banks
Auto Engine image by Andrew Breeden from

Chevy is as American as baseball and apple pie. The body of a Chevy is easily identifiable by shape, size and select characteristics. Cars such as the Chevy Impala SS, Camaro and Nova all have distinct looks, but the big block engine set these cars apart from the rest of the cars of the day. Identifying a Chevy big block engine based solely on the serial number is a straightforward task once the serial number is located and then deciphered.

Step 1

Locate the six- or seven-digit number on the cover of the engine's timing chain. Locate the casting number in between two bolts directly under the GM logo.

Step 2

Decipher the Chevy big block engine prefix. The prefix code is identified by the first few letters. The plant where the Chevy big block engine was manufactured is the first character. The following numbers are the day, followed by the month. For example, a prefix code of T1218: "T" stands for town of Tonawanda, 1218 stands for Dec. 18.

Step 3

Decipher the remainder of the numbers of the Chevy big block engine. This is called the suffix code and identifies the engine by explaining the original casting of the engine and the year in which the engine was produced.

Step 4

Locate the vehicle identification number (VIN). On the majority of Chevy big block engines, the number is situated beside the casting number.

Step 5

Analyze the VIN number verses the reference material. The numbers should match exactly with the vehicle in which the Chevy big block engine came from.

Step 6

Locate the rear intake China wall, also known as the rear intake manifold. Find the code date of the Chevy big block. The code is a letter followed by three numbers and is above the bell housing.

Step 7

Compare the letter in the code to the month of the year. January is A, February is B, March is C, April is D, May is E, June is F, July is G, August is H, September is I, October is J, November is K and December is L.

Step 8

Locate a series of two numbers. This set of numbers indicates the day the Chevy big block was manufactured. For example, "E 11 5" indicates the Chevy big block engine was cast on May 11.

Decipher the final number in the series. This number indicates the year in which the Chevy big block engine was cast. The "5" in the previous example would indicate the Chevy big block engine was cast in 1965, 1975 or 1985. To locate the exact year, refer to the reference material.

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