not that its smart, but I've gone 10.34 on a bone stock rearend with just 3:55 gears, granted only twice. I've run a lot of 11.0's with 1.5X 60's with JUST a set of 8.5" M&H's, absolutely no suspension or mechanical changes from the 1989 trac-lok. I never left the line on the nitrous though, or I woulda probably blown up the rear or broke an axle. The stock 8.8 is a lot stronger than most people think.
Like I said, its not smart, so I'm not bragging. I have a set of c-clip elim 31 spline axles in the garage, but not in the car, yet.