any one know if they make a 4'' soft ride for a 79 F-350.

 

Welcome to the site:
Skyjacker makesa "softride" kit for these trucks. It is not specific to the 350, or 250, but the dimensions are the same. Spring rates are also very similar.
Other manufacturers have kits as well, but this one seems to ride the best.
Many options have been discussed on this site with regards to alternatives for lifting these older trucks. Kits are limited, and a little dated. There are multiple threads that address the use of Super Duty front springs under these trucks. Shackle flips for the rear are also very popular. Much has to do with how much you can fabricate yourself, and how you intend to use your truck.
Happy reading, and again welcome.