How Can You Tell What Year a Chevy Engine Is?by Lawrence Adams
Finding the date code on your Chevy engine is a matter of looking in the correct areas and being able to read the code itself. With little exception, Chevy engine codes are alphanumeric codes with three signs. The three signs represent the month, day and year of the engine and they always appear in this order. Month signs are most often letters A through L representing January (A) through December (L). Sometimes month signs are numerical only, with 1 representing January through 12 signifying December. Once you know the encoding system, date codes are fairly easy to decipher.
Open the hood of your Chevy and locate the engine block. The engine block sits in the center of the engine compartment and contains the pistons, which are easily recognizable in the cylinders of the engine block.
Look at both the front face and rear face of the engine block for the block date code. It will be located on the top edge of either the front or rear face.
Decide which type of date code your block uses, either an alphanumeric or simple numeric code. Read the correct month of production accordingly: A-L for alphanumeric codes or 1-12 for numeric codes.
Read the second and third digits of the block date code. These will number between 01 and 31, denoting the day of the month your engine was manufactured. Sometimes the 0 is left out before the single digits of the first nine days of the month.
Read the final digit of the date code. Most often this contains only a single digit, which denotes the final numeral of a four-digit year. Refer to your car's manual if you do not know in which decade your car was produced. If a manual is unavailable, locate the block casting number beside the block date number. Match your block's casting number to an online list of Chevy block casting numbers, which will indicate the years during which your engine was manufactured. From this selection you will be able to denote the correct decade to which your single year numeral belongs.
- Be patient as codes are sometimes difficult to locate due to many years of engine use. Also, approach this process with some previous knowledge of your car. Knowing the decade in which your car was manufactured will ultimately aid in your deciphering of the third numeral in your date code.