Since you have an LBZ, I'm going to assume that's what you're talking about here. I'll tell you right now, there is no way a stock injector/stock turbo truck will be putting down 550 HP on a 2600 uS pulse width tune unless they are doing something really crazy with fuel pressure. I would say most 2600 uS tunes are in the 480 HP range, 500 tops. Most max effort stock motor LBZ tunes are realistically in the 550 HP area, and they are running more than 2600 uS for the pusle width.
Also, I always get a big kick out of guys who are "safe" tuners. Bottom line, any time you crank these trucks up anywhere near the 500 HP mark, there is nothing about it that is safe! If you want safe, leave it stock (and even then they can still break).