3 1/2" exhaust-Should I?

[68Camaro]

How bad would a 3 1/2" exhaust kill low-end torque on a SBC 355 with a "for now" 274 cam? It's going to get a solid "street" roller eventually and I'm going to spray it. So say it'll make 450-500 with the solid roller + 150-200 shot of nitrous. I was looking at a used nascar side-exit exhaust and adding two mufflers to it. Is 3 1/2" ok and will give me room to grow or should I scrap my plans and stick with a 3"?

Thanks,
Jared

[molyorange 77]

3" is plenty, It takes alotta motor to justify 3.5, I suggest a 3" with a X over pipe.