Best deep muffler for 5.7

[Sean Buick 76]

Sounds louder on the video but a little quieter in the truck.

Resonators and down pipe, really loud when towing the camper. I cant figure how to upload the videos, but its not much better.

I always run my exhaust to the bumper it does help keep the noise down when sitting in the truck.

 

[TylerSteez]

Here's my 454tbi truck with the flowmaster fx oval installed with no cat. You can skip to :035.

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. Video is not the best since it was inside my shop but the idle sound is fairly accurate.

It has no drone, sounds quiet in the cab, idle outside the truck is not obnoxious. Sounds very similar to a magnaflow. If you're looking for a loud exhaust then this is definitely not it but I was surprised when I heard someone else drive my truck down the road last week. Had the shop across the street do an alignment and when he took it for a test drive he went by my shop and I was pleasantly surprised at the exhaust sound I was hearing, sounds strong without being obnoxious and definitely has a more pronounced sound under the load of driving which I never picked up on when I'm the one inside the cab driving it.

 

[b454rat]

Whatever muffler you choose, don't weld it on or use the cheap mufflers clamps. Tighten em down once and it puts a crease and a royal pain to get off. Spend a couple extra bucks n get band clamps, and my favorite, use alot of never seize!!!! Smear it on the inside of the muffler and the outside of the pipe. Yeah it will smoke when it gets hot, but won't burn completely off, making it much easier to remove if you don't like the muffler.

 

[Sean Buick 76]

Whatever muffler you choose, don't weld it on or use the cheap mufflers clamps. Tighten em down once and it puts a crease and a royal pain to get off. Spend a couple extra bucks n get band clamps, and my favorite, use alot of never seize!!!! Smear it on the inside of the muffler and the outside of the pipe. Yeah it will smoke when it gets hot, but won't burn completely off, making it much easier to remove if you don't like the muffler.

I only use V bands. Easy to remove and no leaks

 

[John DeWitt]

I've been studying on this for myself for the better parts of 3 years now. Now i'm not some highscooler who wants to be in a loud shitbox & think himself Dale Earnhardt mind you, a nice deep tone without rattling every baby awake on my way to & from my night shift is what I'm after. I agree with many here, I had narrowed my choices down to the Flowmaster FX or Magnaflow 12468. Specifically these not just for the droneless sound but for the improved scavenging both would provide. If I'm gonna spend money, it better save money. I'm not expecting 15 extra hp or 50lbs of added torque, but maybe squeeze out a mile or 2 extra per gallon. Whatever the gain, gain is gain. I know the 350's enjoy some better scavenging & flow. With that said I have ultimately & for simplicities sake settled on the Magnaflow 12468. Decent open flow, dual-in / dual-out integrated x-pipe, deep tones, improves scavenging, damn near direct bolt up. Of course, I have wondered if running the 12468 & a Flowmast FX directly behind each outlet would maybe create not just better scavenging & flow but a more throaty tone.
Given how much room there is under my 99 Suburban, maybe I'll experiment at some point.
MagnaFlow Performance Exhaust Muffler 12468: 2.5"/2.5" Inlet/Outlet, 5x8x18" Oval, Stainless Steel, Satin Finish https://a.co/d/d7yzpEd

 

[Sean Buick 76]

The best investment is long tube headers. Engines never run right with manifolds. The only scavenging effect will be with proper long tube headers.

 

[John DeWitt]

I agree long tube headers will absolutely provide the best gain in scavenging, but the rest of the exhaust can either support it or diminsh the gain. But if you can point me in the direction of a set that doesn't require beating the side in on one of the tubes JUST to clear the steering shaft I'd be extatic!

 

[Sean Buick 76]

The only opportunity to scavenge the exhaust is the long tube headers. After the headers there is zero opportunity to scavenge exhaust

 

[Scooterwrench]

The only opportunity to scavenge the exhaust is the long tube headers. After the headers there is zero opportunity to scavenge exhaust

Well yes and no. Smaller exhaust pipes will will create some negative pressure behind the exhaust pulse until the pulse hits a resistance such as a bend in the pipe or the muffler at lower RPM's. At higher RPM's smaller pipes create a restriction. Larger pipes coming off the collectors have less scavenging affect but broaden the torque range as do crossovers and X pipes and with less restriction. I choose the latter when designing an exhaust system.

 

[n2xlr8n]

I've paid attention to Calvin Elston over the years- he may be one of, if not THE most talented behind the scenes guys in exhaust science and header fabrication.

In his opinion, the most important factors in exhaust design (for a given engine combination) are-

-pipe diameter, bends immediately after the exhaust port and collector design. <<Funny that; he had no access to available, modern science when he was kicking tail in Nascar...but today it's proven ole Calvin was on the money. He took a lot of grief back in the day from the "in the know" crowd, lol.

I'll add that I've made additional power (as Sean and Scooter mentioned) by using an X-pipe- location is important, so I usually put spray paint in the area where I'm thinking about building it. Where it immediately burns off is where it goes.

I'm going with the Dynomax with the built in X-pipe. I'm a fan of Magnaflow, too.