Originally Posted by 93HybridCX
I don't think you are getting his point..........a 4 cylinder such as your civic CX has one header (not headers).
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About that,,,, I have a pair of headman headers on my D16Z6 its 2 totaly diffrent pipes, one goes to the #1 and #3 and the other goes to the 2 and 4... That is why I have dual exhaust..... And I had a high flow cat on it when I did a smog test and it passed with flying colors, I took it off and went to dual and I ran the same readings for Smog..... So I dont really know if a high flow cat even does anything but look like a cat...