Funny you should ask about gas milage today.. I just filled up and checked the milage. 396 miles on 22.4 gallons. That calculates to 17.678mpg.. I was surprised at how well the mileage is. This tank didnt have many wide open blasts, but im happy as hell if I get 17.5. Ive been driving the truck the same as before the cam swap and got almost 19 last time I checked mileage.