I have true dual 2.5" now on my SS, it sounds/runs good but when I get my cam I will gut the cats and scrap the 2.5 for 3" all the way through. I am still looking for a good x-pipe to run though...

 

I would do 3" i had 2.5 and then went to 3" that was on a 5.3 and it ran great.i would do nothing less than 3" with an 6.0. i am thinking of a 3.5 ture duals.

 

I went with true dual 2.5s on my 4.8, i am pretty much pushing the upper limit for myself, i experienced slight loss of low end torque. I kinda wish i would of went with 2.25s and give my truck more snap and more backpressure. So i figure dual 2.5s on the 6.0 would be sufficient.

Stock piping (2.75 Single) had 8.64 area of flow!

Single 3' has 9.4 area of flow!

Dual 2.25s have 14.2 area of flow!

Dual 2.5s have 15.7 area of flow!

*assuming my calculations are dead on!

 

Scratch those calculations, i was doing circumference. Here is the area:

2.75" Single =5.9
3" Single=7.06
3.5" Single=9.62
2.25" Dual=7.95
2.5" Dual=9.82

So according to my calculations, Dual 2.5" flows a little more than Single 3.5"!

 

go with a single 3", let that beast breath. i had 3.5" on my 98 silverado with the 5.7L in it. the single is cheaper than the duals also.

 

I am going to run a 2.5" exhaust on my 383 and I have 3" cats b/c they flow more so, I am just going to use reducers for them to work.

 

On this a little bit, a 2.5" pipe flows 525 cfm of cold air.....your exhaust is hot so, hotter air moves faster b/c it is less dense. And you need 2.2 cfm/hp you make. So, 1050/2.2=477+hp that can be used from that exhaust.

 

You know, On my 2003 HD with the 6.0 it has dual 3 inch right into the muffler and dual 3 inch out, then it merges into one 3.5 inch tail pipe

 

If you are talking single exhaust I would do 3" for sure.

If you are talking dual exhaust I would do 3" also, you aren't even going to come close to noticing a loss on the bottom end.

 

I think ima go with a 3" true dual setup, I don't wunna have to spend more money down the road to get a bigger exhaust eventhough I probably won't be making 500+hp anytime soon, but one day it will come and I will be glad that I have the 3" setup