I recently had my factory 26 gal fuel tank replaced with an Aero Tanks 52 gallon in the factory location. It does not hang lower than the frame rail, it just extends longer.
My truck is an 07 Chevy Duramax classic but it appears Aero makes a 55 gallon replacement for your truck.
https://www.aerotanks.com/vehicles/ford.html
Best mod I’ve done. Extends your range and allows you to fill up when you want to…not when you need to. I recently filled up where I live in the central AZ mountains for $2.85 a gallon, drove to CA and back passing stations selling diesel for $4.35 with a big ol grin.
