OK, I have decided on a Ravin Z55. What size do I need? Is it 3" in and 2.5" out. I will be running single in/dual out, so do I need to drop to 2.25" out to maintain backpressure or will I be ok? Any input is appreciated. If I get some responses I am gonna try and do it tomorrow. Thanks.

 

yes 3 in and 2.25 out
have it on my truck sounds great
went out on the side like stock

 

All stock pipes are 2.5" so you 2.5" in would be good. If you have the 4.6L, dual 2.25" out would be good. Otherwise, 2.5" DO would be okay.