It's a Corvette. These cars get amazing fuel mileage as they are.
I just did a weekend trip to Akro Ohio in the Vette.
546 Kms door to door. Filled up Friday morning in Gtown, then filled up Saturday in Akron after driving around a bit.
Most of the highway cruising I had the cruise set on 79 mph in 6th gear.
At this level I don't care about gas mileage. Just drive it and enjoy it.