Header and cat question.
 

This one may have been asked before but I didn't see it. Anyway, when replacing the headers on a "S" engine are the primary cats always removed? Or should a 100 or 200 cell high flow cat be put in place? I see many places that sell headers but don't sell or even mention cats with makes me believe they are not necessary. Perhaps the cats come with the headers? I was looking at headers from companies like S-CAR-GO and Instant G. I've seen/heard bad things about B&B exhausts so I'm not so sure about their headers. I hope someone can shed some light on this for me. Thanks.:confused: :confused: