My son owns a very well maintained Ford with the V10.... It only has 65k miles on it and when he is driving very conservatively, he gets 8 mpg.... and when he drives 70 mph... he gets 6 mpg. I seriously doubt anyone with a V10 is getting 14.5 mpg, unless they are coasting off a mountain.My 27ft Coach House 272XL gets between 11-14.5 with the 6.8 V10 and my Roadtrek Versatille with 5.2 Magnum gets 16 mpg. My 2007 Dodge 1500 towing my 245 Terry 5th wheel gets 11.0 with the 5.7 hemi. I used to have a Revcon 32 Ft Prince and 7.5 was normal with a 454 and a RV cam. All the newer ones seem to get better mileage. My VCoach house has the full Banks Power kit on it so I think that is helping my mileage.
Of course your mpg might be averages at 45-50 mph on county roads.
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