Does it actually exist?
Found a guy semi local offering me a 33 gal midship tank from a 78/79 F350 trailer special with the 140" wheelbase frame...I never knew this existed and have never seen it listed anywhere...Google turned up nothing either.

Is this like a unicorn gas tank that I should go grab ASAP?

 

Maybe read this? Maybe it is in there? I posted the 90-96 bronco so you know where to get a skid plate for it.