Fuel mileage is important to me so here's a question maybe Tech Staff and owners can comment on. Currently have '82 with 6V92TA, 36 ft. Averaging in the 7 mpg range. What could I expect in a '88 40 ft with 8V92 Silver? Wondering what two more cylinders and heavier weight does to fuel economy. Usually run about 60 mph and tow 3500 lbs. Thanx for any comments.