Depending on how well/close it was jetted with the stock pipes you will probably need some tweaking. Talk to Dan at Mroz Complete Auto, he has more directly applicable info than most anyone in your area( using that term a little broadly). He has swapped several SPFs to SS pipes( both BB and SB) and can give you a good idea of how much will be needed. His website is
http://www.mrozcompleteauto.com, he's always helpful and also has a chassis dyno if you wanted to have it set up. I believe he has done some of the Windy City members cars over the years and they can give their input. I like the guy, regardless of that extra thumb....I just wish he'd keep it out of his nose :-).