How to Identify a Chevy 4.3 Liter

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The Chevrolet 4.3L was a popular six-cylinder for a variety of truck applications.

The General Motors Chevrolet 4.3L V-6 262-cubic-inch engine evolved from previous V-6 engines, arriving in 1985. This 4.3L was the first to be called "Vortec," a Chevrolet name for all of its advanced truck engines. Essentially a six-cylinder version of the small-block V-8, it is identified by first decoding the engine position in the Vehicle Identification Number, or VIN, and then by locating the engine block casting number and comparing it to a listing of known 4.3L engine castings.

Step 1

Find the VIN tag in the extreme corner of the driver's side dashboard. The tag, best viewed through the windshield from the outside, contains the 17-position alpha-numeric VIN code. Position eight of the VIN identifies the engine. According to the VIN equipment code listing at, the letters "W," "X" and "Z" are used to identify different variations of the 4.3L V-6.

Step 2

Locate the block casting number. On late-model Chevrolet engines, it is stamped on a ledge at the rear of the engine block on the driver's side, just past the cylinder head. According to MRE-Books' small block Chevrolet engine block page, the numerical code is up to eight digits long.

Step 3

Reference the number to a listing of known Chevrolet 4.3L casting numbers, similar to the one found on This listing has a complete section on 4.3L casting numbers which not only identify the years of manufacture, but any specific technical variations of the engine. For example, casting number "535" is a 1992 to 1997 4.3L roller cam engine with a balance shaft and 10-bolt timing cover.