2500 Hd 6.0 Exhaust Question - 2007 Classic

davzog · May 2, 2007

I have about 1500 miles on my Classic 2007 Silverado HD 2500....I think it about time to wake up the exhaust. I want something quiet for towing but with some rumble. After a lot of searching, I had opted for the FLO PRO DI/DO direct replacement muffler and was about to order one.

Then I actually looked under the truck, expecting to see a dual-in/dual out muffler going into a single tailpipe.

Wow...it a has a single inlet and single outlet, bot appear to be 3 1/2 inches in diameter. I was surprised...is this because it is a 2007, even though it is the old body style? Do the NBS trucks have a single exhaust? I dunno!!

So, now I am searching all over again...what to do????

I did find that Flowmaster has a 3.5 inlet and 3.5 outlet offset 50 series big block muffler....I am just wondering how loud that would be.

Anyone know of any other options??? Thanks in advance....

cmadz71 · May 2, 2007

That is very odd. I have a 2005 CC SB 2500HD 4wd with the 6.0L. I was looking for the same type of exhaust you were, a little more aggressive but quiet for cruising and towing. I looked at both the FloPro and Corsa. I finally went with the Corsa Touring side exit.

My stock arrangement was a DI / DO muffler. I believe the inlets and outlets were both 3". After the outlets, it Y'd into one 3.5" tailpipe.

Maybe GM put the new exhaust on the 2007 classics. You'll have to check out a GMT-900 series truck to see if they have the same exhaust set-up. They could have done this since the GMT-900 in the HD series is essentially the same chassis set-up. They'd change the exhaust layout / set-up so the aftermarket companies can make some more money. That way they have a GMT-800 and GMT-900 series exhaust systems.

Good Luck.

davzog · May 2, 2007

I just called Flowmaster, because they have a 3.5 SI/SO 50 Big Block series muffler. The guy (Scott) said he did not recommend the DI/DO flowmaster on the 6.0...too many complaints of it being too loud.

He was surprised the I have the SI/SO, and he thinks that is the new setup for the new body style....so I guess I have more than just some old style body parts on the classic.

He did suggest that the 50 BB series SI/SO would be a good set up even on the 6.0...I may give it a try, but I would like to find someone that alredy has an aftermarket exhaust for the new setup...thanks for the reply

bwinter1 · May 11, 2007

To be honest......I ran into the same problem...

I bought the Magnaflow #15789.....Dual in/One out...... The Magnaflow technical rep pretty much called me an idiot because, "there is a Chevy dealership down the street, and it isn't like the just build the system not to fit." I ordered the system through PerformancePeddler.com (which by the way has seriously negotiable prices, I paid $350 for my system). I ended up taking my truck to a muffler shop and they fabbed up a connector out of stainless that went from the factory 3.5" in to the dual 3" "in's" on the muffler and used the stock connectors for the rest of the system....

The system has a little drone in the cab, but it is a loud MOFO, if that is what you are looking for. I have noticed a little MPG increase even with somewhat of a light foot.

People that have their window down that choose to cruise next be soon roll their window up, slow down or fly by me....

HDdave · May 11, 2007

I went with a true dual system (2 seperate mufflers) because of the stock DI/DO set up. I used Goerlish XLerator mufflers (I had never heard of them, but I decided to trust my muffler shop). They are not chambered like the Flomaster, they have a straisht through design with a perferated core. They looked like glasspacks that were the size of flowmasters, but the guy assured me they werent. Anyways, they sound amazing. A little loud, but thats what I was going for. Its almost silent at 2000 rpms (cruising), but it really screams when it gets tached up.

ws6_guy · May 12, 2007

hmm so GM now does a single exhaust for the HD trucks, well now your open to more si/do setups. On my '05 HD with 3" duals, I plan to buy a si/do Flowmaster Super 44 and go to an exhaust shop and have them fab the dual pipes to a mini y pipe & in the muffler, then dual tips side exit

davzog · May 12, 2007

Installed 50 series Big Block

Had it installed yesterday and it is EXACTLY what I wanted...I got the SI/SO muffler with the 3.5" inlet and outlet. THe muffler guy simply cut off the stock unit (huge) and slide the flowmaster onto the pipes, and welded it in place.

There is absolutely NO DRONE in the cab, and it is very quiet, but has that nice small block chevy rumble through out the rpm range....all the way to 5000 rpm.

You can hear it, but it is almost too quiet. Took the wife for a ride and she had me Get on it with the windows up and with the windows down...then she smiled and said, "I like it"...and she smiled...you guys know that means I get to keep it.....hurrah, a mother's day present for ME!!!!!

I think it will be fine towing the 5th wheel, even up hill at 4000 rpm....it just sounds GOOD.

BTW, I opened the flipper windows today in the extended cab, and it sounds louder...love it!!