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Had a 3" in/out magnaflow on my 5.3 I liked the sound. Just replaced my stock muffler for it but, today I put on a 2.5" bullet and I like it way more. How loud are you wanting to go?
 

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GMFS Señor Member
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I'm also in the market for just a muffler. Just tuning in to this thread and doing some research. I'm wanting nothing too loud...just a nice mellow deep sound. 2008 Silverado 5.3.
 

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not low enough
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I'm also in the market for just a muffler. Just tuning in to this thread and doing some research. I'm wanting nothing too loud...just a nice mellow deep sound. 2008 Silverado 5.3.
up...

never had an exhaust on anything... goin to change this one. i want a low rumble. just BARELY louder the stock. but enough to know its v8..lol
 

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hella cute n shit
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3" inlet/outlet for anything other than the 6.2 and certain 6.0's iirc.

I've always preferred Magnaflows... or a Dynomax Bullet if you want it a bit louder.
 

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Resident Metal Head
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Darren is correct.
07+ 5.3/6.0 has a 2.75" factory pipe size. 3" will slip right over it. Go for that for inlet on the new muffler.

6.2L has 3.5 iirc? Might be 3.25" but pretty sure its 3.5(like 80%+ sure)
 

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hella cute n shit
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'99-07 as well. :thumbsup:

And yeah I'm pretty sure it's 3.5"... I've heard of people running 3.5" and 4" mufflers on the 6.2's.
 

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I have a Magnaflow part#12259 and it is very low rumble at an idle after warm up and great sound soon as you get on it and doesnt drone you out when cruising i have always ran flowmasters before and can honestly say i will not go back after this it is also 3" in/out on a 5.3
 

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I have an 01 gmc sierra rcsb stepside with the 5.3 that i just put a flowmaster american thunder catback kit on. I heard a 3" in/out reduces your mpgs so i went with 3"in/ 2.5" dual out both dumping out the passenger side before the rear tire and it looks/ sounds badass! I got exactly the sound i was going for but may be too loud for some. I went with the 40 series muffler, 70 series i believe would be a little tamer. If I were to do it over again i think i would have done 3" in/ 2.25" dual out for a little bit more back pressure. Mpg didnt change after i started staying off the throttle to listen to the sound!
 

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I have a Magnaflow part#12259 and it is very low rumble at an idle after warm up and great sound soon as you get on it and doesnt drone you out when cruising i have always ran flowmasters before and can honestly say i will not go back after this it is also 3" in/out on a 5.3
That is what I am having installed tomorrow, can't hardly wait!:big_banana_Dance:
 

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hella cute n shit
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I have an 01 gmc sierra rcsb stepside with the 5.3 that i just put a flowmaster american thunder catback kit on. I heard a 3" in/out reduces your mpgs so i went with 3"in/ 2.5" dual out both dumping out the passenger side before the rear tire and it looks/ sounds badass! I got exactly the sound i was going for but may be too loud for some. I went with the 40 series muffler, 70 series i believe would be a little tamer. If I were to do it over again i think i would have done 3" in/ 2.25" dual out for a little bit more back pressure. Mpg didnt change after i started staying off the throttle to listen to the sound!
Backpressure is a myth, it's all about exhaust velocity efficiency and a single 3" exhaust is pretty much optimal for a stock engine. If anything, that Flowmaster is reducing flow thanks to their inefficient chambered design, which also creates a lot of drone.
 

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Go Big or Go home
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im tuning in to since i got a dual 3 and 3 im looking at doing for my truck
 

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hella cute n shit
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I disagree sir! But you go ahead and put on a 3" and have fun with your 14 mpgs!
Lol, yeah okay...

brb ignoring facts for backwoods myths
 

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Some thomas v. nobody posts this crap all over the web about backpressure is a myth and sheep everywhere paste it on their websites and now its a fact. Ill go with what i know by trying different exhausts. You do what you want. I know at 20 you know everything so i should totally listen to you though.
 
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