Hi,
You are starting to get up there in fuel volume. One fuel pump may not have the volume to feed a big block + 1/2 again with the nitros. If you have a 120 GPH pump and 1/2" fuel line it will be barely enough. It's kind of like Russian roulette, if it's not enough fuel and it runs lean....well melted pistons are not fun, if it's enough fuel then hang on for a wild ride.
I have dual carbs and a 110 GPH pump and 1/2 way down the track my fuel pressure drops to 3psi from 6 psi. No big deal as 3psi is enough for my application, however if I had NOS on it ,goodbye pistons.
You have all winter to add a dedicated fuel system for a couple bucks and save an expensive engine, I would go with the dedicated fuel system for NOS.
Good Luck,Perry.
ps- Nitros Tip - You will have to shorten the spark plug gap to about .030 as the extra cylinder pressure will not fire a large spark plug gap, even with msd.