WIN $5,000 For Your Mustang! Enter Now
Talk to a Mustang Expert
1-888-332-7930
Mon-Thu 8:30a-11p, Fri-Sun 8:30a-9p

Free Shipping on Everything. Seriously. Details

SLP Loudmouth Axle-Back Exhaust (11-14 GT & GT500)

Market Price $439.95 You Save 4% ($17.00)

$422.95

FREE Shipping
  • Item 23042
  • MPN# M31023

In Stock Ships same business day. Choose options to add to cart

Features, Video & Details

  • Rich, Throaty Exhaust Sound
  • Muffler Delete
  • 3" Mandrel-Bent 409 Stainless Steel Tubing
  • 4" Polished 304 Stainless Steel Tips
  • Emissions Legal in All 50 States
  • Fits 2011-2014 GT and GT500 Mustangs

Review & Installation Video

Review & Install Video



Aggressive Throaty Exhaust Note. This SLP Performance Parts Axle-Back kit eliminates the restrictive stock mufflers from the 2011-2014 GT or GT500, drastically reducing back pressure to enhance power and to produce one of the most aggressive exhaust notes possible with the factory catalytic converters still installed.

409 Stainless Steel. SLP's Loud Mouth axle-back system is made from 3" mandrel-bent 409 stainless steel tubing, which has excellent flow characteristics and features pre-welded hangers for simple installation. The hand polished, 4" dual wall tips give a show quality muscle car appearance to the rear of your Pony.

Application. Made as a direct bolt on, this SLP Loudmouth Axle-Back bolts right up in the stock location without any modifications required on the 2011-2014 GT or GT500 Mustangs.

Technical Note: Americanmuscle recommends adding the 2005+ Mustang 304 Stainless Steel Exhaust Hanger Kit from the drop down option above, to provide more strength, stability and a cleaner installed appearance. If you have a 2007 Mustang you may need the kit for correct installation.

Fitment: 2011 2012 2013 2014 Details

What's in the Box
Hardware included: Hardware Included
  • (2) Clamps
Installation Info
Tech Specs
Axle-Back Exhaust Specifications
Piping Material: 409 Stainless Steel Tip Material : Polished 304 Stainless Steel
Piping Size: 3" Tip Size: 4"
Muffler Type: None Fitment: 2011-2014 GT and GT500 Mustangs
Will it fit my Mustang?
  • Boss 302 - 12, 13
  • GT - 11, 12, 13, 14
  • GT500 - 11, 12, 13, 14

Most Helpful Reviews

5/5
Loud!

This is an amazing product! It sounds awesome!!! This is a MUST BUY!!!! For some reason it didn't fit right and i had to make a few adjustments, but it was defiantly worth it!

Helpful (1)

5/5
WOWWWWW:O

Like someone mentioned before...no sound clip could do this product justice. I live in California and I am worried about how critical they are regarding the "loudness" of an exhaust. If you are not concerned ...

Read More
Helpful (1)

Overall Rating 4.6 out of 5 stars
Read All 70 Reviews

Customer Photos (14) Submit Your Photo

View All 14 Photos

You Might Also Like

7 Questions / 11 Answers

Ask a Question

will this exhaust sound better with 1-3/4" SLP long tube headers? I am for sure wanting to buy the SLP Loudmouth Axle-Back, but i would like to give it an even rawer mustang sound. i was wondering if that would work or if there was something a little less expensive that would accommodate for the same thing.

stang1195

  • O absolutely! Any headers will compliment the sound of this exhaust.

    giosdad

    Good Answer (0) (0)

Show 1 more answer Answer This Question I need this answered (0) (0)

Will this kit and/or the Rousch axle backfit the 2012 Club America Edition? Comes epuiped with dual factory mufflers. Have the 2012 Mustang Club or America edition. It is a V-6 and want remove the dual factory mufflers and replace with either the SLP Loudmaouth or Rousch axle back exhaust systems.

haze

  • Yes the Club Am is only different trip package is an optional upgrade package for the V6 coupe or convertible which includes a billet style grille with tri-bar Pony badge, front lower fascia with fog lamps, 18 inch sterling gray metallic painted wheels, a unique side stripe, decklid spoiler, and Mustang Club of America front floor mats. I have thr Roush AB,,, OMG, it is hands down the best !!!!

    bobnjamie

    Good Answer (0) (0)

Answer This Question I need this answered (0) (0)

How much horsepower will this exhaust add?

Arthur91

  • An axle back exhaust kit will not add very much horsepower, as the benefit of mandrel bends and larger diameter tubing is so close to the actual exhaust exit. This kit will be mainly an exhaust note upgrade that may or may not free-up an additional one or two horsepower. You're basically buying a more aggressive sound.

    KenobiGT

    Good Answer (4) (0)

Show 1 more answer Answer This Question I need this answered (0) (0)

Will this be LOUDER and/or DEEPER than the Outlaw Axleback I currently have the Outlaw Axleback installed on my 2011 5.0 with a resonator delete. Will switching to the SLP make it MUCH louder? and will it be deeper? because the Outlaws are loud, but not loud enough for me. and I really want a louder exhaust and can't decide on which one to get. So please help me out! thanks

Marco93

  • Would be loader since you are deleating the mufflers but youre not going to be much deeper, to accomplish that you're going to want to look in to an exhaust system (like a cat back system) but in short you're car will be louder but to accomplish a real mustang tone look at American muscles selection of catbacks there well priced> good luck

    Barricade24

    Good Answer (1) (0)

Show 2 more answers Question Resolved

are the slp loudmouths alot louder than the borla ataks? i want a really loud exhaust but also want it to not sound so raspy... I wanted to know if the borla ataks are a lot quieter because I like the sound of them

20145oh

  • The SLP loudmouths are extremely loud. Be prepared to deal with a lot of cabin drone if you get these. In my opinion they are indeed louder than the Borla units.

    smitty77

    Good Answer (1) (0)

Show 1 more answer Answer This Question I need this answered (0) (0)

I got a 14 shelby and ordered the loudmouths, do I have to have the exhaust hanger kit or is it optional?

kb4422

  • With the SLP Loudmouth Axle-Back Exhaust (11-14 GT & GT500), you will not need to purchase the SR Performance Stainless Steel Exhaust Hanger Kit (05-10 All) item #20021 (www.americanmuscle.com/pypes-2005-stainless-hangers.html) however I recommend it for more strength and stability.

    KevinD92

    Good Answer (0) (0)

Question Resolved

More Products You Might Like

Customer Reviews (70) Write a Review

Overall Rating 4.6

out of 5 stars

Installation Time:Afternoon

Installation Cost:0-$100

  • Loudness / Volume 4.857143 4.9
  • Exhaust Note 4.672727 4.7
  • Fit & Finish 4.410714 4.4
  • Bang For Your Buck 4.446429 4.4



  • 3/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    December 03, 2012

    Too much drone

    If you drive at or around 1.7-3k rpm this thing drones way too much. Wish I would have bought a different one. I also set off car alarms when i start my car

    Forster93

    Year: 2013 Submodel: GT Houston, TX, USA

    Helpful (2) (0)

    • Response from AmericanMuscle

      Many people have had success eliminating some exhaust drone by adding an aftermarket mid-pipe to the set up. If you'd like any suggestions on which mid-pipe would be best for you, definitely give us call - we'd be happy to help!

      Lisa , Customer Care

  • 5/5

    Installation Time: Afternoon

    August 11, 2012

    WOWWWWW:O

    Like someone mentioned before...no sound clip could do this product justice. I live in California and I am worried about how critical they are regarding the "loudness" of an exhaust. If you are not concerned with the police, buy it. My mom and dad are a little skeptical about letting me have them now. If you want a calm throaty exhaust, this product is not for you. If you have a "teenage" ego, like myself and enjoy a mean roar...this is for you!!!

    DwightFan

    Year: 2013 Submodel: GT Los Angeles, CA

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    January 04, 2012

    Loud!

    This is an amazing product! It sounds awesome!!! This is a MUST BUY!!!! For some reason it didn't fit right and i had to make a few adjustments, but it was defiantly worth it!

    DJ123

    Year: 2012 Submodel: GT

    Helpful (1) (0)

  • 4/5

    Installation Time: Less than 1 Hour

    November 04, 2011

    They are really really loud and have a lot of drone

    If you want loud, go with these, they are straight through. Idle and low RPM they sound really great. Step on the gas and EVERYONE knows it, at over 3K RPM they really make some noise. Every cop for miles around is gonna know your getting with the program. The bad news is the really drone on the highway at 60 to 70 MPH (now I've got 3.73 gears so it might be less with other ratios). Makes it hard to talk and my experience is that on a long road trip, they start wearing on you. Also when you downshift or get of the throttle, they pop like crazy which I really don't like. Fit and finish is great, can't say anything bad other than I hated the drone and pop (now I'm close to 60 so you younger guys might be able to handle it better). I put on the Ford Racing GT500 in place and they knocked off the drone, but a little quieter than I really wanted. If you want max noise, these can't be beat. American Muscle was the best price on the Ford racing style and shipped them double boxed and they were delivered in 3 days after I ordered them. Got to give American Muscle top ratings.

    steve246810

    Year: 2011 Submodel: GT Kansas City

    Helpful (1) (0)

  • 5/5

    December 14, 2010

    Simply Outstanding

    After the first 30 minutes of having it installed, I was complimented by 3 random people. It is a very noticeable difference from the stock exhaust. I love the sound of it when you get on it. Very loud and will surely turn heads.

    Brett H.

    Helpful (10) (1)

  • 1/5

    Installation Time: Afternoon

    December 11, 2012

    Sounds great, fit is lacking

    Sounds awesome, had these as well on my 2009 GT/ Was extremely excitied to install, only to see they do not fit very nicely on a 2013.....they dont sit flush or centered in the openings, I messed with it trying to get it to fit better, but the way the hangers are on make it impossible to re-arrange. Sounds good, but if you care about your car's looks I'd go with something else. These will be gone as soon as I can afford a different set.

    hastethedav

    Year: 2013 Submodel: GT Los Angeles

    Helpful (6) (0)

    • Response from AmericanMuscle

      I'd suggest taking this to a shop to find out if they are actually defective or if they can be bent a bit to fit better. I haven't heard of this issue previously and I'd like to be able to send you a replacement that fits as it should after we figure out the cause. Please give us a call so that we help you get this resolved!

      Lisa , Customer Care

  • 5/5

    April 09, 2011

    AWESOME!!!

    HOLY CRAP is all I have to say!!! I've owned 2 mustangs and the other one had the pype violaters on my 2010 4.6L, Now I have a 5.0 with these SLP's and OMG!!! Night and DAY DIFFERENCE. I've had 4 people ask me if I took the cat's off or put headers on. When I told them nope its just axle-backs, they said HAHA Yah right... Haha!! WOOH This is the best sound upgrade for this car for the price FIVE STAR!

    Edison

    Year: 2011 Submodel: GT

    Helpful (8) (1)

  • 5/5

    Installation Time: Less than 1 Hour

    January 27, 2012

    Awsome Sounding

    2011 5.0, Manual, 3.73's. It took me and friend about 1 hour to unbolt factory mufflers and install SLP's. SLP's fit right up and positioning them was no problem. Tips look huge compared to stock. Fired the car up, 3 neighbors came out to see what the noise was. The SLP's are LOUD and THROATY, just the sound I wanted. Sound at cruise is moderate, there is drone at 65mph in 6th, goes away at 70 mph, WOT is SICK!!!! There is no video clip that you can listen to that does these things justice. Highly Recommend.

    bushmaster6

    Year: 2011 Submodel: GT Gilbert, AZ

    Helpful (5) (0)

  • 5/5

    Installation Time: Shop Install

    March 04, 2012

    Get This

    Very Aggressive Note but sounds great. I got this for my 2012 GT the week after getting my car. Soooo glad I did. I had a guy in a GT500 track me down and pull me over after passing him at an intersection. He wanted to know what exhaust I had so he could get the same and was surprised it was just an axleback.

    CJ50

    Year: 2012 Submodel: GT Tampa, FL

    Helpful (4) (0)

  • 5/5

    May 24, 2011

    SLP Loudmouth

    Easy install. Didnt even lift the car. Stock mufflers a little tough but I was on my back and the car was not lifted at all. Huge sound difference!! If you want loud, buy this exhaust. Hope to add BBK long tubes and off road X next.

    Chris

    Year: 2011 Submodel: GT

    Helpful (3) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    March 06, 2012

    Sounds good.

    I was worried about having it being raspy but it wasn't at all. This is how is should have came from the factory. Sounds good!!! Hardest part of install is removing the stock mufflers, after that it's cake. If you decide to go with an off road H-Pipe I recommend leaving the factory resonators on. True Story.

    Dude

    Year: 2012 Submodel: GT Dallas

    Helpful (2) (0)

  • 5/5

    February 08, 2011

    Slp 2011

    The product was simple to install took me 25 minutes. Works wonders for the 2011 best bang for the buck

    Ashton Slaughter

    Year: 2011

    Helpful (2) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: 0-$100

    February 21, 2016

    Everything I hoped it would be

    I'm never satisfied with a stock exhaust, even though the Shelby has a great exhaust note from the factory. Basically I was looking to keep the rumble and pop of the stock exhaust and just knock it all up a few decibels, and that's exactly what the SLP Loudmouth did for me. A local shop did the install in about an hour and everything fit with no issues. The longest time was removing the original mufflers. On the initial fire up, I knew I made the right choice. It really comes alive after 3K on the tach, and it's very attention getting. Since mine is a convertible, I get an even better dose of the exhaust note behind my ear, so I can truly say that with the stock exhaust I didn't always hear it, but now it is always audible. This is a cost effective solution for getting more attention. I had numerous people on the very first day making head turns and making compliments. Highly recommended! Thanks again to AM!

    Ratedrsuperstar

    Year: 2011 Submodel: GT500 Columbus, GA

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    January 14, 2016

    sounds like thunder- the best!

    the install was an easy drop in and "bolt on" took about 40 mins to do - it was fairly straight forward and honestly you cant get a better sound from any other axle back than this one. NO raspy kick back - drone is only present during RPM build up (2200 rpms or so) in 6th gear its super quiet. Id suggest NOT cutting off teh resonators. It doesnt add any more hp or TQ and it will cause ALOT of drone and vibration if you do.

    Shawn

    Year: 2014 Submodel: GT Stockton, CA

    Helpful (1) (0)

  • 5/5

    September 11, 2014

    You will not believe the difference

    I have a 2012 Shelby, I liked the stock exhaust sound, but I wanted more. I installed these pipes and it is a different car. it is THE BEAST! You can now hear every bit of the 600+ horsepower. Warning: It take a lot of finesse to not make a lot of noise, but when you open it up, the volume, depth, and voracity of the exhaust is nothing short of amazing. It there is an exhaust that is louder, I cannot imagine it. The car now sounds like it eats small children and pets. The exhaust was the only thing I changed. I would not have believed the difference. This is what a V8 muscle car should sound like..

    MustangFanatic

    Year: 2012 Submodel: Cobra Virginia

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    March 27, 2014

    Bought these and was so excited until

    It took me about 30 minutes to take the stock mufflers off, and once I put the slps on they were about 3 inches off and the tips wouldn't even go on cause the pipes were directed right into the rear valance. I was lucky to of had a shop to be able to bend the hangars to fit and it took about 2 1/2 hours to get them to fit flush. Kind of disappointed for the price you pay and then they didn't even angle up right it took, like in said almost 3 hours to get them perfectly straight and level. But with all that said, it was worth every minute spent on doing this. These really bring the life out of your mustang. The 4" tips look amazing and the sound really is worth any trouble you might have to go through. I highly recommend this product to anyone looking for axlebacks.

    2011mustangGTRyan

    Year: 2011 Submodel: GT New Jersey

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    March 01, 2014

    2014 slp loud mouth

    All I can say is night and day !! What a difference compared to the stock mufflers slp loud mouth brings out the true mustang my 5.0 sounds amazing and makes the car even more fun to drive !!! Fits nice and looks good also sounds great !!!

    floridaboy18

    Year: 2014 Submodel: GT

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    July 15, 2013

    SLP Loud Mouth is the Axle back to have

    I recently had these installed on my 2012 GT500. And all I can say is wow! These things sound much, much, much, more aggressive than your stock muffler. If you want a throaty, deep rumble, then these are the ones for you. People will hear you coming, no doubt about it. Even at low RPMs they growl to let people know, "there is something coming and it sounds angry!" Highly recommend!

    TB1906

    Year: 2012 Submodel: GT500 Las Vegas, NV, USA

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    April 16, 2013

    Pure wow!

    I just installed these today on my 2011 5.0 and man did my car come to life! For those of you who are looking for a mellow exhaust, walk away now! These bad boys are LOUD! Nice and loud startup/warm up, really nice and deep "burble" on idle that gives the car an "I'm ready and waiting" attitude at a volume that is not too loud but rather just perfect, and an absolutely STUNNING and just pure raw wide-open throttle sound. Definitely a must-have for those of you who are looking for a pure, raw sound. Mustangs have always had a unique sound as opposed to other V8's in its class. With an SLP Loudmouth axle-back exhaust system, you can make sure they know what you have and they will never forget the sound.

    LiveReckless010

    Year: 2011 Submodel: GT

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    January 12, 2013

    Great sound - Lots of compliments

    Been running these for 8,000 miles, and couldn't be happier. I commute 30 freeway miles each way - they're loud, there's some drone and I knew that going in. Probably should take it easy around cops, although all the cops I know love the sound. It's an aggressive sound, not for softies or those living in HOA areas, but it's my opinion that the Coyote should sound this way from the factory. Install is as painless as could be, but I had to cut a notch in the hanger bracket because the hanger arm rattled against it. They also sound great with straight cat to axel pipes.

    302cdk

    Year: 2013 Submodel: GT LA, CA

    Helpful (1) (0)

Related Mustang Categories