Dual exhaust?

[2004Sierra6L]

I've looked all over before posting this, and just can't find what I'm looking for. So here's my issue, I have a 2004 Sierra 2500HD and I'm wanting to put dual exhaust on it. My dad recently put duals on his 06 2500HD with the 3 inch pipes into two mufflers, with 2.5 inch tailpipes, with 3 inch tips. I thought about getting the same setup as him, but my friend with a 2003 2500HD said that 2.5 inch tailpipes is too restrictive and that I should run 3 inch tailpipes. I would like to run the 3 inch tailpipes because I personally think it looks better under the truck having a meatier looking exhaust, if you will. But my biggest concern is the 3 inch too big? Will it cause power loss? Or does it even really matter? Thanks in advance.

[davester]

My '04 Sierra with a 6.0L gas runs a dual exhaust into a single muffler, with a single 3" output from the muffler. It's stock.

 

It's not going to matter 2.5" vs 3" for dual exhausts.

[Grumpy Tooch]

I got the Magnaflow kit had it custom fit to my ext cab (they only make for crew). It sounds great and performs great. No need for 3", it could actually make the 6.0 run worse. From the factory it has 3" from headers to cats, then all 2-1/2". I've always has dual exhaust on my trucks and never felt need to increase to 3"

[Caleb G.]

I know that its always been kind of a rule of thumb that you don't want to go from having a big exhaust down to a smaller exhaust because it reduces air flow. the 5.3 chevy has a smaller exhaust because of the size of the engine and how much exhaust it puts out. the 6.0 has a larger exhaust because it is a larger engine. by having a non-restrictive exhaust it gets the heat away from the engine quicker in turn making it run well. Hope this helps.

[newdude]

JBA Exhaust part # 40-3030. Do it. I had it on my 2006 regular cab. ZERO drone, helicoptering, etc. Great sound, but cruising down the road it was near stock level of quiet inside which I loved. Awesome when you gave it any amount of gas.

 

http://www.jbaheaders.com/searchresults.asp

 

If I had another 01-06 I'd buy it 110% again. They have you cut right in front of the muffler. The kit is dual exit on the right side of the truck. These older trucks had a true dual setup to the muffler and any sort of y piping happened after the muffler, so this kit completes the true dual.