First thing... Use complete sentences with some punctuation. This isn't English class, but we can't hear you physically speaking so that we can understand what you are saying. Right now it's just a string of words.
I think that you are saying...
You have an LT1 Camaro [year?? could be important] with open hearders and 250 lb. nitrous shot. You also have $600 burning a hole in your pocket and want to know how best to spend it.
Any other mods, like rear gears, trans shift kit, torque converter, cold air intake? Are the stock PCM and O2 sensors still in use?