For 1980 and earlier vehicles, oils having one of the following service ratings MUST be used: SE, SE/CC, or SF. For 1981 and later vehicles, use ONLY SF rated oils; it is O.K. to use an SF oil with a combination rating, such as SF/CC. Under the classification system developed by the American Petroleum Institute, the SF rating designates the highest quality oil for use in passenger cars. In view of this, it is recommended that you use an SF rated oil an ANY Corvette. In addition, Chevrolet recommends the use of an SF/Energy Conserving oil. Oils labeled "Energy Conserving (or Saving)," "Fuel (Gas or Gasoline) Saving," etc. are recommended due to their superior lubricating qualities (less friction = easier engine operation) and fuel saving characteristics. Pick your oil viscosity with regard to the anticipated temperatures during the period before your next oil change. Using the accompanying chart, choose the oil viscosity for the lowest expected temperature. You will be assured of easy cold starting and sufficient engine protection.
Some fuel additives contain chemicals that can damage the catalytic converter and/or oxygen sensor on late model engines. Read all labels carefully before using any additive in the engine or fuel system.
Fuel should be selected for the brand and octane which performs best with your engine. Judge a gasoline by its ability to prevent "pinging," its engine starting capabilities (cold and hot), and general all-weather performance. As far as octane rating is concerned, refer to the "General Engine Specifications" chart, to find your engine and its compression ratio. If the compression ratio is 9.0:1 or lower, in most cases a regular grade of gasoline can be used. If the compression ratio is 9.0:1-10.0:1, use a premium grade of fuel. Vehicles with a compression ratio higher than 10.0:1 (1970 and prior-check the engine chart) should use a premium unleaded fuel, with an octane additive if it is available.