New to Nitrous
5psi for the fuel, 900psi for the bottle. Start small and retard your timing accordingly. What's your ring gap?...and do you have forged pistons, ARP rod bolts, etc??
When I ran the bottle on my old 360 combo, for a 180 shot I ran 27° timing, 5psi fuel pressure, NGK -9 plugs, all MSD ignition, + 110 race gas (only when I was spraying it, for detonation prevention). This took my car from 13.8's in the 1/4 mile to 11.1 @ 122mph in Denver Colorado.