It's been many years since I checked it but if I recall when we took it on vacations it would run in the 16-18 range. The 2.56 would let that 400HO run at a fairly low rpm at high speeds. At that time it was real leaded premium fuel too. So a lot of the milage robbing stuff in gas today wasn't a factor. But around town and with many fast starts it was much more thirsty.

Don't know if any of you have ever noticed but I've always thought that the long needle and wide travel on the Bird's gas gauge, relative to most vehicles, makes it appear to drop faster.