In my experience, 9-11 is typical mpg for these old squares in city driving. 13-15 highway mpg is what I would expect - less with towing or heavy loads. A big heavy non-aerodynamic vehicle does not get good gas mileage. A 1/2 ton truck in perfect condition with highway rear axle ratio and careful driving can improve 2-3 mpg. On newer 1/2 ton pickups, I got 19-20 mpg with a 2000 Silverado V6 work truck, and 15.5 mpg with a 2010 Sierra ext cab 4.8L V8 - all city. Like the car ads say: "your mileage will vary."
