Some truth here. Some slants are hogs it seems. But my Dad's '68 valiant 225 got 28 mpg doing 70 on I-25 going back and forth 100 miles each way to work. I think if they are "right", mid to higher 20's can be common. I've had 318 2bbls get better over 20 easily. I think my brothers Aspen R/T with the 4 speed OD got 26 mpg on the road. It went on a lot of trips. Clean burn, valves that seal, timing spot on makes a big difference. Huge in fact.
