The EPA estimates for gas mileage on a Corvette with a 430 hp engine and automatic transmission vary depending on the model year and specific configuration (coupe vs. convertible, etc.). There's no single answer. However, you can generally expect to see figures in the
low to mid-teens for city driving (mpg) and perhaps the high teens to low twenties for highway driving (mpg).
To find the *precise* EPA estimates for a particular year and model, you should check the EPA's fueleconomy.gov website or consult the owner's manual for that specific vehicle.
