the all controversial MPG arguement

Haven't had a BB in many years, but I believe the 18-19 mpg at cruise. At one time I had a 360 powered Cordova, don't remember the rear ratio. I had to replace the cam (bought that way cheap), so slight upgrade, did a trhee angle valve job with 33 degree seats, recurved the dist, and rejetted carb (dist and carb were ongoing). I had a Zemco on board mileage computer, and had a approx 40 mile drive loop for checking. Got it up to about 24 mpg hiway, but never could get more then 16-17 in combined hiway/town, and about 13 in town