I bought a powershot NOS kit and i have 100HP jets in it now am i flirting with disaster if i install the 125HP jets on my hyper. pistons?

I believe it would be. Maybe someone else will chime in.

Safest = 0 NOS
Safer = 50-75 shot
Safe = 100 shot better have Timing and fuel right.
Bearable = 125 shot better have Timing and fuel right Hypers don't give warning signals until poof ... its done.
Don't even ask ! = 125+

Seriously is 25 hp hit worth it? Its a fact Hypers and juice don't mix well anyway. If you do make sure you keep the fuel coming and the timing is dialed in. GL if you try it. I wouldn't recommend it myself.

I know guys that are running a 200 shot with hyper pistons but they are running ign. retart. Like Tex says you have to make sure your timing is right on.Oh yeah another suggestion run a cheap head gasket they are cheaper to replace! No expert still in the learning stagesjust my .02

Horsepower will not hurt your cast pistons. Detonation will. Pull 4 degrees out of your timing and run a little fat on the carb jetting. Make sure you don't hit it until your above 3k rpm and have a fuel pressure safety switch wired in and you're good to go. I've personally run 200 hp of nitrous on a turbo-intercooled 2.2 Mopar four cylinder with CAST pistons with no issue back in the late 80's. Just watch the basics. And hang on. :thumbsup:

Is your ring gaps wide enough? I personally would not put a 125HP shot on hypers. If you do what is required to make it safe (pull timing, richen it up) how much HP are you actually going to gain? My guess would be not much (10-15HP) at the risk of losing your engine. While I agree detonation is the "main" thing that kills pistons, heat is up there too. You might get away with a 250 shot, but for how long. Just because they don't fail the first or second pass doesn't mean they aren't going to fail on the 5th pass. How many passes do those pistons have with a 100 shot on them?

Running a weak head gasket is not a good safety feature. Often times when you blow a head gasket there is or can be damage to the deck and/or head surface.