I just took my mileage over my trip to Connecticut this weekend. I had 20 miles of regular city driving on my tank when I started my 140 mile trip. After that 160 miles, I put on another couple miles and filled my tank.
I was suprised when I got 15.5 miles to the gallon. Very plesantly suprised indeed!
I have a freshly rebuilt carb (myself) as well as new fuel, air and oil filters and next-to new NGK plugs.