Muffler of Choice?

Tom P said:

Looking for a better-than-stock flowing muffler that doesn't get too loud or has too much drone at highway speeds. I have a 2000 K3500 with 7.4L and do a bunch of towing with the family so I dont want to drown anything out. Would prefer a straight through design like a magna flow but I know there are a hundred options. Need to do 2 in and 1 out for a single 3" tail pipe. Love how the flowmasters sound but I don't think they flow nearly as well the other brand mufflers. What have people had success with? What do I need to stay away from?

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Flowmaster 70 series. It growls when taking off and starting the engine but quiet going down the road. since you have a BB 454 you might want to have duel exhaust out the rear w/without resonators. I have a single 70 on my 2007 GMC sierra Classic with Pacesetter heads and the rest is stock. Sounds great on the outside but quiet on the inside. Flowmaster did inform me that the Cats from factory already flow well.

The Flowmaster 70 is still a chambered muffler design and is likely to be more restrictive than a straight through design like the Magnaflow or Jones Max Flow. The Flowmaster is also a more expensive option. I'm personally sold on the Jones Max Flow. It's design is like the Magnaflow at less than half the price. The numbering for the mufflers is also surprisingly similar. For a 2 inch, offset/center, 14 inch body muffler, the Magnaflow number is 11224 and the Jones number is MF1224 (first muffler size I saw when I searched). Do they come off the same assembly line?

Blackwater said:

Flowmaster 70 series. It growls when taking off and starting the engine but quiet going down the road. since you have a BB 454 you might want to have duel exhaust out the rear w/without resonators. I have a single 70 on my 2007 GMC sierra Classic with Pacesetter heads and the rest is stock. Sounds great on the outside but quiet on the inside. Flowmaster did inform me that the Cats from factory already flow well.

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Not a bad plan, but one Jones Max flow with a 3" tail pipe will more than suffice vs. dual flowmasters which would more than double the cost of the project. Right now I'm looking at $175 for muffler and mandrel bent tail pipe with a 3" to 4" diameter 12" long polished stainless tip. The flowmaster 70 is $160 alone, and then probably another 175 or more for the tail pipes. Yes the factory cats flow well because they are a straight through honeycomb desing, but my truck has 175K on it. I discovered the drivers side cat has been removed (probably because it was plugged) and the passenger side cat is still there (probably because its to difficult to access under the tranny mount). So we are going to cut out the remaining cat and weld in a test pipe and then new single muffler and tail pipe.

Okay Dokay

I also agree with the borla muffler! Me and a buddy have the exact set up with the 5.7 longtubes (he has a X pipe) I have a H pipe with a borla xs pro.. mine isnt installed completely yet but his sounds AMAZING.. no cats

I have the exhaust and am ready to go but my welding skills are non existent so a guy from work is going to help me and we both are fairly busy right now. As it stands we are looking at next Monday night to get it done. At first glance I'd say the Jones is a well built muffler. Unpolished stainless which doesn't bother me but the welds are all solid and it's got some heft to it. The tail pipe I found on eBay is 3" mandrel bent with one joint. I'm very excited to hear the results. Should be a deep mellow tone.

I love my Thrush welded dual in/dual out muffler. They are cheap as hell too.

big_mike said:

I love my Thrush welded dual in/dual out muffler. They are cheap as hell too.

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I loved mine until one of them rusted out and blew apart 2 years into duty.

My experience with thrush mufflers is that they drone way too much and rattles your interior apart. Not sure if that is the case with all the thrush mufflers.

My experience with thrush mufflers is why bother? They are almost as quiet as a factory muffler.