Chevrolet part number is Group 0.027 #3990914. This is the later style with a stop in case the mount tears and was used as a recall on almost all cars.
Will work on Full size Chevy, Chevelle, Camaro and Nova models. There are a few different styles of these relating to the distance between the tabs for installation on the frame bracket (this one measures 2 5/8" between the pads), and how tall the mount is from where it mount to the engine to where it mounts on the frame pad (these are 1 5/8"). Which mounts you need depend on your frame pads. Check before ordering but this is the most common mount and we cannot know which pads you have on your car.
Mounts are in great shape and not used or deteriorated. The item "NOS GM #3990914 SB Chevy Motor Mounts Impala Chevelle Camaro Nova LH & RH Pair" is in sale since Thursday, December 6, 2018. This item is in the category "eBay Motors\Parts & Accessories\Vintage Car & Truck Parts\Engines & Components\Motor Mounts". The seller is "datedcomponents" and is located in Hamburg, Pennsylvania. This item can be shipped to North, South, or Latin America, all countries in Europe, all countries in continental Asia, Australia.