Hey Andy!
There's a section in the IHRA Rulebook under Super Stock called "Super Stock Production". Starts on page 42...
http://www.mydigitalpublication.com/...on/?m=1203&l=1
SS/PAA through SS/PJA are for automatic transmissions, and SS/PAA through SS/PJA are stick cars. "-1" is for 4bbl carbs, and "-2" is for 2bbl carbs.
Give it a read, and holler back with any specific questions you might have.