If you are talking about NHRA Super Stock...you have some very limiting factors that will cost a ton of money to buy if you're not going to do them yourself. To run at the top of the class will take a serious time commitment. Nostalgia Super Stock is a nice alternative, and it allows all kinds of engine mods, yet mocks the vintage SS look.
Super Stock requires: Factory Carburetion, Factory Heads (Modifications are legal and necessary to run at the top, but the factory casting numbers must be there ...906), Factory block with stock stroke, factory size over-bore allowed (not sure how far you can go...want to say .060), and any size cam shaft.
It's always been a dream of mine to run in the NHRA Stock Eliminator or SS class, but when you factor all of the above along with the fact the NHRA will have Sportsman racers on site of a National Event from Wednesday-Sunday...or later...It just doesn't make sense. Maybe when I'm old, rich, and retired=Never; (