have a new chevy express passenger van 2500 regular body, 4.8 liter V-8. 14.5 in town and 17.5 highway. had a small gulfstream b+ motorhome built on a chevy cutaway van with a 6.0 liter gas engine, it got 11mpg to 12mpg. btw the express van is hardly broken in so mileage may increase a little.