How to Identify a Chevy V6by Floyd Drake III
Chevrolet's V6 engine did not exist until 1977. That was the year Chevy introduced the 90-degree V6. General Motors, Chevrolet's parent company, has been producing V6s since 1960. Chevy used GMC V6s in trucks from 1984 to 1987, until replaced by a Chevy V6. Chevrolet V6 identification is easy, both visually and by using engine ID numbers.
Confirm that the Vehicle is a Chevrolet. With the exception of the 1984 through 1987 pickup truck model years, Chevrolet for more than three decades has only used the Chevy V6. So if it is a Chevrolet built since 1977, chances are good it has the Chevy V6 engine.
Identify the engine as a 6-cylinder. The best way to differentiate a 6-cylinder engine from other engines is to count six spark plugs, three on each side.
Locate the ID number on the engine block. According to Nasty Z28, the numbers are located on the passenger side of the block behind the distributor. On a front wheel-drive, look behind the distributor.
Decode the engine ID number. The Chevrolet engine ID number is usually seven to eight digits long. It features numbers and letters, with a prefix and a suffix. The suffix is three letters long and identifies the engine size, horsepower and vehicle model. In engine number V0106CMJ, for example, "CMJ" is the suffix. The preceding prefix numbers supply information about the date and location of the vehicle's production.
Contact a Chevrolet parts department with the full engine ID number. They can decode it for you. Or you could visit GM Parts Direct online. Either type the number in the search box or send a message to the customer service department and they will decode it for you.
Identify the casting lug-nut on the engine block. It is located on the right side as you face the front of the engine, towards the bottom. There will be a lug nut attached to a stud. According to HotSixes, differentiate the size V6 using the following data: the 200 c.i.d. has no lug nut; the 229 c.i.d. has one lug nut; and the 262 c.i.d. has two lug nuts, one on the right and left sides of the block.