I had a 96 GC limited 5.3L or 318. I knew the mileage would be bad on my 07 Hemi. I am seeing about 14.6 MPG (Highway and city)- Highway driving only (75+ MPH - this past weekend - 60 mile trip), I saw about 17.2 which was not bad. I have been told that Hemi gets better gas mileage than the 4.7. I have always had a V8 in my vehicles but I almost wish I would have gotten the Diesel (20 - 24 MPG). However I love the power of the Jeep Hemi. It is all a choice we all have to make and the nice part there are many choices. If have a need for POWER – HEMI if not 4.7 will work, good gas mileage Diesel. Just my two cents.