3.5" muffler options for 6.0L?

[RecklessWOT]

I recently acquired a 2008 GMC 2500HD w/t utility body. I don't love the truck, I plan to keep it a year or two to use for getting stuff done while the 'Burb is in rehab (living in the new garage and getting restored). The muffler is rotted and the tail pipe is bent and cracked at the seam from someone backing into a snowbank or whatever, I fully knew that going in. I planned to throw on my spare 3" thrush chambered muffler I had in the basement and salvage parts of the bent tailpipe to make it exit before the rear wheel, but just noticed today it has 3.5" pipe back there. I looked online for mufflers, and with the exception of spending almost $200 on a Flowmaster 50 series I can't find any real options. I don't care if it's a glasspack or a chambered muffler, it just has to fit and be reasonably priced. Cheap would be even better. I noticed some of the short bullet type mufflers for sale in 3.5" for like 40 bucks, but I have no experience with them. Is that like louder than a glasspack? I like loud, but if its stupid noisy on such a new vehicle that's sure to get the attention of some bastard inspector. Anyone have first hand experience with them? Any suggestions? I'm all ears at this point

 

[80BrownK10]

Anything cheap on eBay if you search that size pipe and muffler

 

[QBuff02]

just buy a reducer from autozone or some other local part store that goes from 3.5" to 3" and put whatever muffler on it you want.

 

[TubeTruck]

^^^What he said

 

[bucket]

If it still has the converters on it, I'd just replace the muffler with straight pipe and a tailpipe. Sounds pretty good imho. And cheap!

 

[Catbox]

Have your 3" chambered muffler expanded to match the pipe that it will attach too under the truck.

My racing buddy used to do this to Flowmasters all the time.
He would get 2-1/2" mufflers and have them expanded to 3" to fit his needs.
It does not affect the muffler as it is just making the inlet / outlet larger.

 

[Craig 85]

On a 2016 Ram 2500 (6.4 Hemi) I ran the Flowmaster 50 Series HD. It's nice because the core is 3.5" also. I got a horrible drone though. I added this Dynomax Ultraflo #17224 "bullet" muffler to help. It took away some more of the drone. From the second picture you can see, it's just a glorified glass pack. These are about $75 on Summit.

Ultimately, I had to go with a 3 chamber Flowmaster to control the drone on the hemi. I keep debating putting the FM on my Denali, since the 6.2 has 3.5" exhaust also.

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[RoryH19]

Have your 3" chambered muffler expanded to match the pipe that it will attach too under the truck.

My racing buddy used to do this to Flowmasters all the time.
He would get 2-1/2" mufflers and have them expanded to 3" to fit his needs.
It does not affect the muffler as it is just making the inlet / outlet larger.

If you are going to have a muffler shop weld it on they can do this as part of the installation.
Takes about 10 seconds on their machines.

 

[RecklessWOT]

I work in a machine shop and I have a welder at home, I suppose I could just make that 3" I have fit the 3.5" pipe. I just figured that might be kind of restrictive. But if not, hell I'll do it.

I'd love to just straight pipe it because the cat is still there and I'm sure it would sound mean as hell, but I'm not sure about inspections. I know a guy that will pass anything as long as it's nothing OBD related (that has to get reported to the state) and not something legitimately unsafe (super rusty frame, etc). He's on the honor system, doesn't even really look at it, but god forbid some cop says "hey that sounds really loud" and notices the truck has no muffler whatsoever, I don't want dude to get in trouble. Loud is fine, but I'm gonna say there probably has to be some kind of muffler on there at least

 

[bucket]

I believe catalytic converters qualify as mufflers. It's how Chevy got away with the active exhaust option on the late model Corvettes and Camaros. Over a certain % of throttle, a valve moves in the muffler and bypasses all the noise reduction.