Currently, I have an 5.4L 3V 05 with the Ford Racing/Borla SI/DO set up and thinking of going to 2.5" duals all the way to the back. I have the mandatory X pipe that I managed to scavenge out of a GT 500 but the it's a bit splayed out so thinking of something closer together.

The question is, how will it sound with Magnaflow round mufflers with a 14" body? I am thinking 2.5" in and out and keeping the pipes after the FR/Borla muffler, they're already there and look sweet especially with the squarish Ford Racing tips.

Question is, with this set up what will I loose or gain? I am running a Edge Evo with canned tunes but there is a Gryphon upgrade in my future. I don't want to mess with the current cats yet, got to find out what my warranty will handle. Yes, warranty, I only have 50K on the truck. So opinions are helpful.

 

It will sound good, but the 4 cat's are really going to hold it back. You might lose some low end because of the pipe size. If you can get the tailpipes to work, then that will save you some cash.

I wouldn't count on the GT500 X-pipe working. Everyone here just uses universal X-pipes from Magnaflow and certain ebay brands.

 

You won't be able to use that X pipe. This is what you need...

 

Thats what I thought, ah well, something to sell on EBay. I was thinking the Hi-Flow cat set up but I want to check and see how my warranty is affected before I go crazy with the sawzall. I was also thinking about going down to 2.25 before the mufflers and 2.5 out the back, so many possibilities.

 

I believe removing any properly functioning cat with less than 80k miles is illegal which should pretty much answer the warranty question as well. Definitely stay 2.25" b4 the muffs or you might be dissapointed with the torque curve.

 

I'm running 14" Magnaflow round bodied mufflers w/ Magnaflow hi-flow cats and 2.25" piping and it sounds pretty good, real throaty and deep. It sounds even better now that I've fixed the exhaust manifold leaks I had.

 

I had 2 40 series flowmasters with 2.5" pipe. Loved the way it sound. Has a nice deep sound without any piping. I friend of mine has a magnaflow with a turn down on his chevy 5.3 and is to quiet. It's not much louder than my truck was stock.

 

There's your problem.

 

^ exactly

 

Magnaflow dual in/out part# 11379 that's what I have search on youtube frpp hotrod cams and my truck will pull up