Additional fuel carrying capacity on pickup

Re-reading my 2012 Super Duty brochure, only the the long bed Super cab and crew cab diesel trucks got 37.5 gallon tanks; all other diesel combinations got 26 gallons; and, all the gas trucks got 35 gallon tanks. I believe those were the configurations from 2011 through 2017 when all the diesel tanks got larger. On a long day we would end up stopping for fuel 2 to 3 times at the one fourth point of 18 to 19 gallons. After switching up to a larger fifth wheel and getting tired of stopping that many times a day, we had a Ford dealer replace the OEM tank with a Titan 50 gallon tank. Already having a short bed we didn't want to give up the bed space. We love it! We only stop once a day (or not at all) with the big tank. The Ford dealer changed the truck programing so the fuel gauge and the miles to empty work correctly. It's a hoot to see 689 miles to empty when we're not towing and the mpg are higher.