Now that I have done my 3" lift, there is room now to do a true dual exhaust system. I went to my muffler shop and he said x pipes are better. What is the difference between them power and torque wise? Thanks in advance. I have the 4.6l, so I will just do 2.5" pipes, remove the Y pipe, and run 2 pipes down the center into 2 different Flowmaster super 44's, then straight out under the rear bumper. I already have hollow rear cats.

 

Take the hollow cats off, you don't want your exhaust to slow down, hollow cats=expansion chamber.

iirc x pipe gives you more power on high end. Check some youtube videos, the sound changes as well.

 

Yes x pipe. Everything I have read about true duals has said use an x. I'm putting true duals on mine and that's what I'm gonna use. Be sure to upload a video when you get it done!

 

^ This. The power difference is very slight between the two, but an X will sound better IMO.

 

Is it hurting performance that much? I have had other F-150 owners and yes other brand owners tell me how sweet the truck sounds with the current set up( stock Y pipe,cat deletes, si/so Flowmaster, exit out in front of rear tire. I would think with the x pipe and 2 mufflers it would sound even better, no?

 

It can. Best practices would say put a piece of pipe in its place, you want to maintain velocity of the exhaust.