This set of Autolite 65 spark plugs is a great addition to any collection or for use in a variety of vehicles. With a thread diameter of 14 mm and a hex size of 21 mm, these spark plugs are made of copper and have a voltage of 12 V. The spark plugs are compatible with many models from 1958 to 1992 from AMC, GM, and Mopar. Their OE/OEM part numbers include 4864457, 4091713, and 5213693. These spark plugs have a standard configuration and an installation depth of .75 in. They are not vintage parts and are not considered a performance part. These spark plugs are designed for use with gasoline and have interchange part numbers RN12YC, N12YC, RN12Y, and N12Y.