Cat back issues after lce header?

I'm toying we the idea of going with LCE header on my 2.7l. But I am wondering if I will run into back pressure issues past the cat converter. Anyone put on a header on the stock engine/exhaust and then found out they needed to increase the diameter of the exhaust past the cat?

 

2nd gen here but running 2.7 with LCE with oem catted midpipe and Gibson catback. The pipe is bigger diameter on catback. I did run it for awhile with oem catback/header and changing the catback only changed the sound but didn't notice that it freed up anything per butt dyno and tripometer.

 

"butt dyno". Nice (lol)! If I read your response correctly, you ran stock with the header and catback, then changed out to the LCE header and Gibson catback? Was there a time you ran the LCE header with the oem catback?

 

Yes, I did run LCE header with oem midpipe/cats & oem catback. The Gibson catback went on last.

 

Gotcha. Good to know, thanks! So you never saw much of an issue with back pressure then it sounds like.