Greetings, I've searched high and low and not found much in the way of guidance on my situation so I'm hoping posting it here will trigger the interest and kind input of the wealth of knowledge and experience this forum has, thank-you in advance.

Here's my situation: I have a 2014 Fx4 screw with the 6.2L. I love Borla but Borla doesn't provide a cat back system for my truck, they say the one for the Harley might fit but no guarantees. Anyways, so I started looking at what I could do with a custom setup. First, I could find nothing on my existing factory exhaust...so i crawled under my truck and did some measuring and this is what I found. The header pipes have a cat in each pipe, these pipes merge into a 3.5 inch pipe. This 3.5 inch pipe is connected to a 3.0 Inch pipe which contains the resonator and remains 3.0 inches back to the muffler. From the muffler out is a single 3.5 inch pipe. I've read that this can sometimes help with the flow of the exhaust, other forums I've read this may cause a bottleneck, so there are many opinions on the subject of pipe sizes and I love to hear them all!

So i've ordered a Borla XR-1 round muffler as a replacement for the stock resonator. This one is 3.5 inches in and out, 15 inch body so I will replace the factory 3 inch pipe with 3.5 inches o the new Borla resonator then 3.5 inches out to a y pipe which splits to dual 2.5 inch pipes to enter my now Borla 2.5 dual in/2.5 dual out muffler. From here back will be dual 2.5 pipes to the exit. Note, i ordered the dual in/dual out exhaust because it was the one in my favourite sounding cat-back kit from borla. A couple of things I'm wondering and looking for comments and opinions on...1. could I lose anything noticeable such as low end torque, or backflow issues by going from the 3.0 pipe to a 3.5 pipe? Any opinions on performance gain as it may be? Thanks in advance, all replies are appreciated!

 

So i climbed under again with a pipe caliper and seems some of my previous measurements were wrong (first time measured outside circumference with a tape.). So the primary headers are 2.5 inches into a 3.5 pipe. This 3.5 pipe is connected to a 3.0 pipe which s reduced to the 2.5 inch intake on the resonator. From the resonator back to the muffler is 2.5 then, it's 3.0 to the end with a 3.5 chrome tip. So, i'm replacing all the existing 2.5 pipe with 3.5, then connecting with a y pipe with 2.5s out to the dual an and dual out 2.5s to the end with 3 inch tips...input appreciated an yes, i did read the exhaust sticky before posting

 

I wouldn't worry about power difference, because exhausts don't do anything for these trucks for performance as far as I'm concerned. They definitely won't do anything with stock manifolds and cats. I have long tube headers and no cats, all mandrel bent exhaust, and barely noticed a difference, though that's on a 5.4. I'd do it all for sound, which I'm sure you'll be happy with because Borla is the only muffler worth buying and the 6.2s sound amazing.

Also, wheel base is the only thing that matters for exhausts. If the Harley catback is for a supercrew with 5.5ft bed, it'll fit. If you have a supercrew with 5.5 ft. bed., or even if you have extended cab with 6.5 ft bed, it'll fit. And then if you have supercrew with 6.5 ft. bed, they sell an adapter that adds 12" to the catback to make the SC 5.5 kit bolt right up.

If by back flow you mean back pressure, that absolutely won't be an issue.

These will fit your truck, either with or without the adapter depending on bed length:

http://www.borla.com/products/f150_s...t__140404.html
http://www.borla.com/products/f150_s...t__140383.html

I'll also suggest taking a look at Roush exhausts, because unless something has changed, Borla manufacturers special mufflers just for Roush, so they have Borla mufflers as well. They're considerably cheaper as well, but I guess they use 409 SS now instead of the 304 SS mine is made out of. No way I'd pay $900 for a catback. And Roush systems don't differentiate between 5.0 and 6.2 fitments, which was my suspicion anyway. I doubt, though I don't know, that the factory cat-backs are too different between the two engines. I have a Roush catback behind my headers and Y pipe and it sounds great.