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

Item 18423
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      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.

      Product Information

      Features, Description, Reviews, Q&A, Specs & Installation


      • 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


      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

      Flowmaster 817511

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (100+)

      Write a Review

      Ratings Summary

      4.9 out of 5 overall rating from 100+ customers

      Installation Time: Afternoon

      Installation Cost: 0-$100

      • May 06, 2020

        5 2005 GT - Douglas007 Installation Time: Less than 1 Hour

        Great exhaust

        Would buy these again . Great sound . Get a lot of comments on the sound. Head turners

        Helpful (0)
      • April 03, 2020

        5 2006 GT - MI619 Installation Time: Less than 1 Hour

        2006 Mustang GT

        These are some awesome pipes. I am 45, and I don’t mind the noise. A tad bit of drone at around 2,000 rpm. But, when you jump on it, these pipes scream

        Helpful (3)
      • January 30, 2020

        5 2008 GT - Blackedouts197 Installation Time: Less than 1 Hour

        Sound like a nascar!

        I have an offroad x pipe paired with these outlaws and people on street always giving me thumbs up and filming my car their cell phone! Next step is the hot rod cam!

        Helpful (6)
      • January 28, 2020

        5 2007 GT - RichardG Installation Time: Weekend

        Awesome Exhaust Sound

        Flowmaster Outlaw Exhaust sounds awesome. Much more aggressive sound. I'm very happy I selected the Outlaw for my mustang.

        Helpful (5)
      • January 17, 2020

        5 2010 GT - Brocobra Installation Time: Less than 1 Hour

        2010 GT

        Sounds great at low rpms. Cheap to install at a shop. Would buy again.

        Helpful (4)
      • January 15, 2020

        5 2008 GT - XxTracyxX Installation Time: Less than 1 Hour

        Flowmaster Outlaws

        This was a good purchase! They make a big difference in the sound of your Mustang. If your looking for an aggressive exhaust for a low price this is definitely the best option. Sounds awesome.

        Helpful (3)
      • January 08, 2020

        4 2008 GT500 - JosephGT500 Installation Time: Afternoon

        Sounds Great GT500

        Install was easy, took me about an hour with hand tools. Very! loud over stock. There is a drone. Will take some getting use to. Overall I'm happy with it. My GT500 actually sounds like a muscle car now

        Helpful (3)
      • January 02, 2020

        5 2005 GT - Lvl100Magikarp Installation Time: Shop Install Installation Cost: 0-$100

        Old muscle sound

        This exhaust system has been terrific, the sound reminds me of the 60-70's era muscle car sounds. Would recommend this to anyone who loves that type of roar.

        Helpful (4)
      • December 12, 2019

        5 2006 GT - HeadTurner Installation Time: Less than 1 Hour


        If you love a good Beasty sound you need to invest in this exhaust. I've had this exhaust for 5yrs and it is still sounds beautiful.

        Helpful (3)
      • October 29, 2019

        5 2009 GT - ToddA Installation Time: Less than 1 Hour

        Flowmaster outlaw axle back

        They have my 09 GT sounding great easy to install. It has a deep tone. My neighbors love at 5 in the morning lol

        Helpful (4)

      Questions & Answers (59 answers)

      5 Top Rated Questions


      • 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

      Helpful (11) Show 3 more answers

      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!!!!

      Helpful (5) Show 2 more answers

      Im looking for exhaust to fit a 2010 mustang that sounds like a Lamborghini, any ideas? This one sounded like it may have that same rumble/sound.

      • These would be two completely different motors and would no exhaust for a 2010 Mustang will sound like a Lamborghini.

      Helpful (4)

      im assuming you dont need a tune for this???

      • Axle-back exhausts generally will not require a tune.

      Helpful (2)

      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.

      Helpful (2) Show 2 more answers
      10 More Questions
      Borla s type or flowmaster outlaw, which one have deeper sound? 1 answer
      I have a 2005 Shelby GT500...will these work? 1 answer
      Will the Flowmaster Outlaw Exhaust pass Pennsylvania state inspection? 1 answer
      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 1 answer
      I currently have muffler deletes on my 09 gt but want something different but similar loudness would this be what I’m looking for ? 1 answer
      how would these sound paired with an X pipe? 1 answer
      I’m looking to upgrade to long tube headers on my cammed 2009 gt. I was suggested to add a muffler for back pressure since I’m currently catless and muffler less. Will these give me the back pressure needed for the performance and maintaining the loudness I love so much?! 1 answer
      I have a question about this flowmaster outlaw ? Is it louder than a MBRP axle back which one is louder ?? 1 answer
      how do these compare to the corsa extreme axlebacks?? 1 answer
      From what I've read about the outlaws they have a mean rumble, do they have any crackle to them? 1 answer

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (2) Muffler assemblies
      • (2) Clamps

      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

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