Thanks Red69, but I think I have my answer, from 1 of the nations, and top end exhaust suppliers of factory correct systems, about repro chambered exhaust systems for BB Camaro’s. I have a repro stainless steel system that is 2” system. My initial question on this was, initiated by my engine builder, “ Do you really want this 2” system behind your Stainless Steel headers, 2 1/2” collectors, and 2 1/2” E-cut outs”? Have not gotten a clear answer from anybody about the difference in 2” to 2 1/2”, as far as suppression, hp loss, sound, behind my freshly re-done L78. Of course the above exhaust expert, response on the chambered with cut outs, why cut outs, cause the chambered was going to be very loud. And off course no response from vendor on the od’ issue, and yes I ordered as BB set, paid for BB set, will not answer my return calls. Last conversation was they would check with manufacturer to get these answers. Hum, wonder where the manufacturer is! Not going to name the vendor as I know the policy of this forum and CRG in general! Again Thanks.