Actually, the USS Barbel, SS-580, was the first of class. Two others were built after her, the USS Blueback, SS-581, and the USS Bonefish, SS-582The USS Barbel was the last diesel sub ever built in the United States. It's a fairly modern design, and I guess it could be fixed up with modern electronics and attack systems.
They were, for their time, a fairly radical new design that many vessels have been based on since. First production tear drop design in the US, first US sub to use a control center in the hull instead of the sail, etc.
Barbel was commissioned in January 1959 and decommissioned in December 1989, 31 years later. Pretty good service life for a diesel sub. They had 2600 ton displacement, a 19,000 mile range unrefueled, 6 21 inch tubes, 18 torpedoes, 15 knot surface speed, and 21 knot submerged.
The other two, USS Bonefish was commissioned in July 1959, and USS Blueback in October 1959.
USS Blueback is now a memorial in oregon, since 1994.