Hyper pistons are fine to run. KB told me their hypers would handle a 200 shot with no issue: AS LONG AS YOU FOLLOW THIER RING END GAP GUIDELINES!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
I personally wouldn't run a nitrous kit with a mechanical fuel pump. IMO if you are gonna spray a motor you are beyond the stock fuel systems capability. Now can they work ....I suppose and there are very knowledgable guys using them but I would not and I don't reccomend you do either. You can run electric fuel pump for the motor and the kit but it needs to be at least a 140-160gph HQ pump something like the Mallory Comp 140 or Edelbrock 160 or BG 400. I prefer to run 2 regulators. One bypass regualtor for the pump and carb and then I tap into the supply line before the bypass regulator and that goes to a dead head style regulator for the kit. Fuel pressure and nitrous pressure gauges are a must and the best way is so they are visible to you while driving so you can keep an eye on them.
