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Flowmaster Outlaw Series Axle-Back Exhaust (05-10 GT, GT500)

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  • Item 18423
  • MPN# 817511

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    Features, Videos & Details

    • Super Aggressive Flowmaster Outlaw Sound
    • Durable 409 Stainless Steel Construction
    • 2.5" Mandrel-Bent Tubing
    • 4" Polished Stainless Steel Tips
    • Includes Two Flowmaster Outlaw Mufflers
    • Fits 2005-2010 GT, Bullitt, and Shelby GT500

    Review & Installation Video

    Hey everyone I’m Justin with, and today we’re going to be breaking down the Outlaw series Axle-back from Flowmaster for the 2005-2010 Mustang GT. Flowmaster calls this their most aggressive Axle-back system available for the late model 46 Mustangs. This entire kit centers around these two outlaw series mufflers, which to the casual observer, hardly resemble mufflers at all, but rather highly engineered resonant tubes, which are responsible for that super aggressive tone. Like many other Flowmaster kits the Outlaw series features 409 grade steel construction and 2.5” mandrel bent tubing. It also features this very sleek black finish, which is going to be great at resisting corrosion. Everything exits out of these dual 4” polished tips, embossed with that classic Flowmaster logo. Installation of this Axle-back is very straight forward and should only take you about an hour using some basic hand tools. Now let’s hear how the Outlaw series from Flowmaster sounds compared to your factory exhaust.

    Super Aggressive Flowmaster Sound. Give your Mustang that unmistakable Flowmaster sound with the Outlaw Series Axle-back exhaust system from AmericanMuscle. This system improves exhaust flow using Flowmaster's race-oriented style Outlaw mufflers for that super, aggressive exhaust note your high powered Pony deserves.

    Quality Construction. Constructed from durable 2.5" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties the Flowmaster Outlaw Axle-back features two race-oriented mufflers with massive 4.0" diameter polished stainless steel tips for impressive muscle car looks and sound. As an added bonus the tips are embossed with the "Flowmaster" logo for true custom styling.

    Application. This Flowmaster Outlaw Series Axle-back exhaust system is designed to fit the 2005 to 2010 GT, Bullitt and the 2007-2010 Shelby GT500 Mustangs for both great looks and great sound.

    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: 2005 2006 2007 2008 2009 2010 Details

    What's in the Box
    • (2) Muffler assemblies
    • (2) Clamps
    Installation Info
    Tech Specs
    Axle-Back Exhaust Specifications
    Piping Material: 409 Stainless Steel Tip Material : Polished Stainless Steel
    Piping Size: 2.5" Tip Size: 4.0"
    Muffler Type: Straight-through Fitment: 2005-2010 GT, Bullitt and Shelby GT500
    Will it fit my Mustang?
    • Bullitt - 08, 09
    • GT - 05, 06, 07, 08, 09, 10
    • GT500 - 07, 08, 09, 10

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    Most Helpful Reviews

    You will love them...your neighbors won't!

    I am not big on writing reviews but after installing these, I felt AM and Flowmaster deserved a review. First off, thanks AM for getting these to me in less than 24 hours, can't ask for much more than ...

    Read More
    Helpful (38)

    What will you decide?

    Before purchasing these, you have to ask yourself a question: Do I want to continue to live a mundane, 9-5, stock exhaust life? Or do I want to frighten small children, have women flock to me in droves, ...

    Read More
    Helpful (17)

    Overall Rating 4.9 out of 5 stars
    Read All 100+ Reviews

    Customer Photos (71) Submit Your Photo

    View All 71 Photos

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    37 Questions / 13 Answers

    Ask a Question



    • Outlaw is plenty loud all by itself. If you want to amp it up try some long tube headers paired with an h pipe. But trust me they're good all by themselves


    Show 3 more answers Helpful (9)

    How do these sound on a V6 with true dual? Do you have a sound clip available?? I removed the X brand because of cabin drone... will these create a drone on the V6? Thanks


    • I have sound clips of a 2009 V6 with the ford racing dual exhaust that uses a true dual setup and the same mufflers as the bullett mustang, and the Flowmaster Outlaw. The Outlaw provides a much deeper throat tone to the exhaust making it more like a V8 sound. It has a little bit of drone at certain RPM's however it really gives the V6 a muscle car sound. The closest thing I can relate it to is the new Boss 302 Laguna Seca. IT SOUNDS AWESOME!!!!


    Show 2 more answers Helpful (5)

    I have the Pypes muffler deletes on my 05. Are these Flowmaster Outlaw axle back louder and have a deeper sound than the Pypes muffler delete's? Cant really hear the difference between the video's


    • The Pypes Muffler-Delete Axle-Back Exhaust (05-10 GT, GT500), item # 20022, ( may have a slightly higher pitched sound than the Flowmaster Outlaw Series Axle-Back Exhaust, The Flowmaster's are going to have a very deep sound that is also loud. It also depends on what other exhaust mods you have made. Different headers and mid pipe will drastically change the sound of the car as well.


    Helpful (1)

    Do the Flowmaster Outlaw series Axle-Back Exhaust add horse power to your Mustang.


    • That is a big yes and they sound real good and meaty.


    Show 2 more answers Helpful (1)

    I have Duel exhaust on my 2008 V6 mustang, can I put GT axle-back exhaust on it ?


    • Yes the Flowmaster Outlaw Series Axle-Back Exhaust will fit your 2008 V6 with a true dual exhaust conversion.


    Helpful (0)

    Hey does these exhaust come with black tip?


    • We currently do not have the Flowmaster Outlaw Series Axle-Back Exhaust with the black tips no.


    Helpful (0)

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    Customer Reviews (100+) Write a Review

    Overall Rating 4.9

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:0-$100

    • Loudness / Volume 4.810811 4.8
    • Exhaust Note 4.871622 4.9
    • Fit & Finish 4.584459 4.6
    • Bang For Your Buck 4.755932 4.8

    • 5/5

      Installation Time: Afternoon

      June 18, 2013

      You will love them...your neighbors won't!

      I am not big on writing reviews but after installing these, I felt AM and Flowmaster deserved a review. First off, thanks AM for getting these to me in less than 24 hours, can't ask for much more than that. Secondly, I am a very amateur wrencher, I've done the majority of the work on my car minus my cam installation, and these went in perfectly. Removing the old hangers is a different story. Removing rusted in bolts, located where only a 9 year old girls hands could reach was a pain, so it took me a little longer than the typical hour long install noted by other reviewers. My suggestion is putting penetrating oil on the (8) bolts the night before, and using anti-seize during the re-install. Now to the good part, I have basic bolt-ons including Steeda cold-air kit, Comp Stage II VSR cams, Kooks long tube headers, and a custom tune. Previously I had Flowmaster American Thunders mounted which I loved but after watching a few re-runs of Monster Garage and hearing the phrase "if you can't hear it before you see it" kicked around, I decided to get something a bit less dainty. Let me tell you, these make my GT sound like an absolute terror coming down the street. Some days I will go out and cruise around in 2nd gear and will be giggling like a little girl the entire way. It is definitely an acquired sound, differing from the AT Flows with their low and lopey sound. These sound more like a semi-truck rolling down the thruway. Like many other reviewers, it does have a decent amount of drone; I'm geared at 4.10's so I get it around 1800-2200rpm. It can be a little annoying but it is easily remedied by giving it a little more gas. And WOT is simply devastating. If you enjoy driving down a city street and setting off every car alarm along the way, or getting the finger by the Audi driver next to you who can't hear his blu-tooth phone call, then the Outlaws are for you.


      Year: 2005 Submodel: GT Buffalo, NY, USA

      Helpful (38)

    • 5/5

      Installation Time: Afternoon

      May 17, 2014

      What will you decide?

      Before purchasing these, you have to ask yourself a question: Do I want to continue to live a mundane, 9-5, stock exhaust life? Or do I want to frighten small children, have women flock to me in droves, and send Camaro owners home crying to their mommies? If you choose the latter, these pipes are for you. Mean and nasty, they sound incredible when driving downtown between buildings. They do drone, so be prepared for that. But it is a small price to pay for the new found prestige,respect and glory that will be coming your way. I had mine installed by by the muffler shop so not sure on the install time for these. Technician pulled them out of the box and said, "Oh man, it's THESE!" After they were installed, all the guys in the next door transmission shop came out to see what the ruckus was all about.


      Year: 2007 Submodel: GT

      Helpful (17)

    • 5/5

      Installation Time: Afternoon

      November 03, 2012

      So much better than....

      I installed the Pype Bombs first and had a rough time with the fit. These are so much better fit and finish, these were easy to align and center in the cutouts and the sound is amazing!!! I think the tone is deeper than the Pypes and don't sound so steel canish. In my opinion spend the extra money and go with Flow Master first.


      Year: 2006 Submodel: GT Mississippi

      Helpful (13)

    • 5/5

      Installation Time: Less than 1 Hour

      October 18, 2013

      No Two Flowmasters Are The Same

      I was running a set of 60-Series Flowmaster axle backs on my 2008 Bullitt for the last year or so. They sounded ok driving around town, but I never liked how tin-canny they sound when you open it up. Still, I tolerated them. But something happened a week ago that sent me looking for a better-sounding exhaust. I was driving with my girlfriend in her car when a Subaru WRX with one of those silly potato cannon exhausts rolled up alongside us. My girlfriend looked over at me and said, "Hey, that sounds just like your car." I was so horrified that I began researching for a new set of axle backs immediately after returning from dinner. After hours of research and sound clips, I was torn between the Pypes Pype Bombs and the Flowmaster Outlaws. I decided to go with the Outlaws based solely on the customer feedback. I crossed my fingers and placed the order. In the back of my mind, I was very concerned that the distinct Flowmaster tin-can sound would still be there in these Outlaws. I was also concerned that the Outlaws wouldn't be much different from the 60-Series set I already had. I was worried that I had made the wrong decision. Let me tell you in no uncertain terms that I am 100% happy with my decision now! The sound of my Bullitt can no longer be compared to a Subaru with a potato cannon! As a previous reviewer said, they don't call these things "outlaws" for nothing. I would estimate that they are at least 40% louder than the 60-Series. They have a very deep, sinister rumble at the lower RPM's, and when you step on the gas they just absolutely ROAR. My daughter was driving behind me last night and she said the inside of her car was vibrating when I would take off from a red light, and I wasn't even putting the hammer down. These axle backs sound so amazing that I have to wonder why Flowmaster would manufacture pipes that are anything less than these Outlaws, and I wonder why any Mustang owner wouldn't want their pony to sound exactly like this. You don't like loud? Then what are you doing in a Mustang? The only bad thing I can say about the Outlaws is that they do not bolt on perfectly with the tips centered in the exhaust cutouts. Yes, they can be adjusted, but Flowmaster should've just manufactured these for the 2005-2009 Mustangs and left out the 2010, which would probably solve that issue. I had them installed by a local shop. I'm not sure where to rate these on the obnoxious scale because it really depends on what kind of neighbor you are. If you want your neighbors to hate you, you can certainly accomplish that with the Outlaws. Run down the street in 1st or 2nd gear and you are sure to scare people out of their underwear. They may tolerate you if you take it easy, but they will still hear you coming or going. If they can't appreciate that American muscle sound, maybe they're not worth the consideration anyway ;) In closing, I highly recommend the Outlaws to any Mustang owner who wants their pony to sound like a lion roaring on the Serengeti Plain. I promise you won't be disappointed.


      Year: 2008 Submodel: Bullitt Lansdale, PA, USA

      Helpful (12)

    • 5/5

      Installation Time: Less than 1 Hour

      September 27, 2012

      Amazing product! Very aggressive sound.

      VERY loud and VERY awesome!! aggressive through and through. i have received no negative feedback and all compliments. my gf even loves them!! definitely recommend this to anyone!!!


      Year: 2006 Submodel: GT Aransas Pass, TX, USA

      Helpful (9)

    • 5/5

      Installation Time: Less than 1 Hour

      August 28, 2012

      Absolutely Amazing!!

      if you want your mustang to have a "ballsy' aggressive sound this is definitely the exhaust to have! Flowmasters are the best out there and this exhaust proved that. easy install and had it growling in no time. Great product!!!!


      Year: 2005 Submodel: Cobra

      Helpful (9)

    • 5/5

      October 16, 2011

      Flowmasters Finest

      Bought these before American Muscle even had them and they are truly unbelievable. I have them on with a bassani x pipe, headers, steeda CAI, and couple other bolt ons and these things scream. Flowmasters loudest product by far. They DO NOT quiet down after 3k rpms like most chambered flowmasters, they get louder. These and slp's are evenly matched in loudness surprisingly but these are better because its flowmaster. Definitely not for daily driving.


      Year: 2005 Submodel: GT Staten Island. NY

      Helpful (9)

    • 5/5

      Installation Time: Afternoon

      November 15, 2012

      Very aggressive sounding!!

      This is an awesome sounding exhaust. I installed it on an '09 GT500. The only issues with installation is removing the stock exhaust. You either have to cut the stock hangers or remove the hanger brackets. Installing and alinging them was really easy. If you like to get attention from bystanders, you'll get noticed with these. At 2000RPM's I'm getting a significant amount of drone inside the car tho, hoping this will lessen when they are good and broke in (for better terms). Completely recommend tho!! This is NOT your typical Flowmaster's, They are BETTER!


      Year: 2009 Submodel: GT500 Fort Rucker, AL, USA

      Helpful (8)

    • 5/5

      Installation Time: Afternoon

      August 02, 2012

      Great on GT500

      What an improvement over the stock mufflers! after having muffler deletes on two other Mustangs.(2006 and 2010 GT) these deletes are better by far. quieter on cold start up so you don't wake the neighborhood. nice and loud with no popping when you let off the gas. loud with a grown up growl. by far the hardest part of installing these on a GT500 is removing the stock mufflers!! due to a nicely hidden bolt head between the muffler and frame. but once you get the stockers out, your home free, requires 2 sockets and one wrench. tips lined up nicely in the rear cutouts, took my time and required 1.5 hours.


      Year: 2010 Submodel: GT500 New Mexico, USA

      Helpful (8)

    • 5/5

      Installation Time: Less than 1 Hour

      July 08, 2012

      Amazing difference

      These pipes are EPIC! I just bought my '08 GT/CS about a month and a half ago and the only real "problem" I had with it was that it was WAYYY too quiet. After reading reviews and checking ratings, I decided on this axle-back system and I can easily say I do NOT regret that decision. These pipes are LOUD, they turn heads, they demand attention and having done nothing else to the car (yet), it already has the loud aggressive sound I wanted for it. I highly recommend them to anyone. Install time was roughly an hour maybe hour and a half on the lift in our garage. The hardest part is taking off the stock mufflers, I still have the scratches to prove that one!


      Year: 2008 Submodel: GT Annapolis, MD

      Helpful (8)

    • 5/5

      Installation Time: Less than 1 Hour

      January 03, 2013

      Angry exhaust

      Mufflers are real aggressive. They definitely get you noticed. Snaps a neck almost every time. Great sound. Better in person as compared to sound clip.


      Year: 2007 Submodel: GT500 Sayville, NY, USA

      Helpful (7)

    • 5/5

      Installation Time: Less than 1 Hour

      September 12, 2012

      Awesome Sound!

      This axle back sounds great! Super easy install took 20 minutes from start to finish and fit perfectly. I know my car isnt any faster but it sure sounds like it....


      Year: 2007 Submodel: GT500 Pahrump,NV

      Helpful (7)

    • 5/5

      Installation Time: Afternoon

      August 03, 2012

      Great Sound!!!!

      Easy install; sounds great, real good over 100mph worth every cent.


      Year: 2010 Submodel: GT Germany

      Helpful (7)

    • 5/5

      Installation Time: Less than 1 Hour

      April 19, 2012

      Best sounding exhaust I have heard on a mustang !

      I own and operate an exhaust shop in orlando, fl and have been working with the v6 and v8 stangs alot lately and this by far is the best sounding system I had magnaflow on it before but owner disliked how quite it was so we installed this system in less than 15 mins and instantly the car came alive and reminded me of the old 351 clevland Thumbs Up to FLOWMASRTER!!!!


      Year: 2010 Submodel: GT Orlando, FL, USA

      Helpful (7)

    • 5/5

      Installation Time: Less than 1 Hour

      November 13, 2013

      Amazing on V6!!!

      I purchased these awhile back with the Pypes true dual conversion kit.I can honestly say that these mufflers are amazing. Super aggressive exhaust note. Very minimal drone on highway or cruising speeds. Some drone at around 3000 RPM or so. Nice subtle tone while cruising but when you put the pedal to the floor they scream. Installation went relatively quick I had to make some modification here and there with the Pypes kit to get them to fit where I wanted them. The best bang for the buck, truly love these Mufflers. Here is a video of them installed on my Mustang.


      Year: 2005 Submodel: V6 Justice, IL, USA

      Helpful (6)

    • 5/5

      Installation Time: Afternoon

      March 17, 2013

      Best exhuast for your Mustang

      I looked at three Flowmaster axle back systems. American Thunder, Pro Series and Outlaw Series. I ordered the Outlaw Series. I was worried it would be to loud but I am wayyyy happy with it. It is loud but it is a pleasing loud and on the highway you can still talk in the car or listen to the radio or do like I do and just listen to that sweet exhaust note. I love it and I am happy with my choice. I installed it in about an hour. Five bolts on each side for a total of ten. Two on each hanger(two hangers per side) and the clamp where the pipes meet. It took no time to line up each exhaust tip in the bumped cutouts. I am not a wiz with tools and I almost took it some place to have it put on but I am glad I saved the money and did it myself. I say for the sound and money this is the exhaust up grade you are looking for!!!!!!!!!! Hope this helps you make your choice.


      Year: 2006 Submodel: GT Akron, OH, USA

      Helpful (6)

    • 5/5

      Installation Time: Afternoon

      November 14, 2012

      Awesome wishes it sounded this good!

      OMG! OMG! OMG! These things sound absolutely AMAZING!!! I couldn't be happier. They're not just loud, but they give my '10 GT the growl that epitomizes a true muscle car. Installation was pretty easy. Fit was fine. There were some minor scratches on the muffler itself...but nothing anyone would ever see. I did take it by a local shop and had them tighten the clamps...they didn't even charge me. I'm a very happy camper.


      Year: 2010 Submodel: GT Aledo, TX 76008, USA

      Helpful (6)

    • 5/5

      Installation Time: Less than 1 Hour

      September 13, 2012

      OH YEAH....

      This is an outstanding exhaust system, but it is definitely not for the faint of heart though. It is incredibly aggressive and sounds awesome. Great start up sound, incredible when accelerating and even when idling you get the sound of a monster grumbling. Running through a tunnel or an overpass and hit the gas...everyone takes a look.


      Year: 2007 Submodel: GT500 San Antonio, TX, USA

      Helpful (6)

    • 5/5

      Installation Time: Afternoon

      April 28, 2012

      Flowmaster Outlaw Series Axle-Back Exhaust

      Great Sounding Exhaust I was very anxious to put them on my 2010 GT. They have a classic muscle car growl when idle and they roar like raging thunder when letting the throttle out. After I installed them you could really tell the difference between the stock mufflers and the new FlowMasters. The exhausts look great , and the material these exhausts are made of is very durable and they should last a long time. Great fitment, installation was an hour and a half and only a few tools were needed. This is a project that can be done in your garage, jacked up in your driveway or on a lift at an auto craft shop. Now when my vehicle rides through any town I leave crowds staring and people compliment me on the sound.


      Year: 2010 Submodel: GT Clinton, MD

      Helpful (6)

    • 5/5

      Installation Time: Less than 1 Hour

      March 08, 2012

      2008 Mustang Bullitt

      I purchased these for my 2008 Bullitt and they are awesome. These mufflers sound unlike any other exhaust that I have ever heard. They have the flowmaster sound, but there is also a distinct burble sound. They work well with the car and turn many heads. I would definitely recommend them to anyone.


      Year: 2008 Submodel: Bullitt Jackson, TN

      Helpful (6)

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