Most 5.0's have stock forged pistons, sometime in '92 Ford swiched to hypt pistons, which arn't quite as strong, but the forged one's are pretty strong. The only thing about spraying a large shot is that the slightest bit of detonation, on a big shot won't be slight at all, and the stock components will be more likley to fail. As long as it is tuned, you should be ok to a point. Then it comes to not being the nitrous that kills the engine but the tq and hp output. Weather nitrous, or a blower, you can overload your engine. The only thing I could see nitrous doing is the fact that since a higher percentage of air in the combustion chamber will be oxygen, it will burn hotter, which can lead to detonation, which as I said, is bad, especailly with a poweradder.