this is a light car 2700lbs. glide,373 gear, 11.6 comp, m2 ported track 1 227's, super vic, 1000hp, and 300hp nos.

My non-nitrous 422 uses 1.875" primaries and 3.5" collector for a 3500lb Chevelle. Given the amount of nitrous you're using I'd be looking for 2" stepped to 2.125". Give Lemons headers a call and they can steer you in the right direction.