Dually Gas Tank

[DuallyDave]

I have a 93 cc dually. It has been sitting for over five years. The fuel pump is dead and I decided to replace the tank as well. Searches are coming up with two choices. A 25 gallon and a 31 gallon. How can I tell?

Thanks all

 

[88GMCtruck]

Short bed = 26 gallon, long bed = 34 gallon.

 

[DuallyDave]

Short bed = 26 gallon, long bed = 34 gallon.

Thanks!