Who is BS'ing who?

When I took my 408 on the Car Craft Antitour it was about a 600 mile round trip. On one leg of the trip I did see 13 mpg and it probably averaged 11mpg.
On all kinds of roads mountains, towns, and freeways.

68 Dart
408
4:10
28" tire
gear vendor overdrive

Car is not really dialed in for fuel economy just an out of the box carb installed with no real tuning to say. I'm sure there is potential to get at least a couple more miles to gallon.