My guess it that is will be a variant of the Gato, according to wikipedia they are pretty much the same accept for the different pressure hull allowing it to go deeper.
http://en.wikipedia.org/wiki/Gato_class_submarine (Gato class characteristics)
http://en.wikipedia.org/wiki/Balao_class (Balao class characteristics)
http://www.battleshipcove.com/ss298-history.htm (some good information about the USS Lionfish a Balao class sub that is at Battleship Cove in Fall River, Massachusetts)