Recommend a Gato Class model. Larger than 1/350.

Ultimate is the 1/72 Revell. There's lots of aftermarkets for it now, depending on what specific boat you want to model.

Trumpeter has a couple of 1/144 versions (a 1941 and a 1944) that are pretty nice.

Than. These look great. I am going to build the Wahoo.
Which would you suggest?

For the Wahoo, the Trumpeter 1/144 Gato -1944. The conning tower looks right on that kit for the Wahoo.

I need to stop reading books. Just read about the USS Laffey and bought a model to di it. Now reading about the USS Wahoo, so want to build it. Oh well. I don't suppose there would be any detail sets for the Trumpy Gato?

Give Google a run for their money Darrell. There seems to be some WEM PE sets still kicking around as well as something from Nautilus...even some conversion stuff:

http://www.squadron.com/1-144-White-Ensign-Gato-Class-Sub-Detail-Set-p/we14401.htm

http://nautilusmodels.com/Gato/144Gato.htm

http://www.cybermodeler.com/hobby/details/nau/detail_nau_144201.shtml

Probably more if you dig deep enough. Accurate Model Parts has some decals for this scale as well.

Iron Bottom Sound Models also has some 1/144 Gato update sets. A lot of conning tower conversion for Balao class boats but also deck guns.

http://ibs.eastcoastarmory.com/Csets3.htm

I've been trying my had at making an aftermarket periscope set for the 1:72 Gato. It's slow work but i think the results are a tad better than the model kit scopes. Every now and then i'll make a set and put them on ebay.