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

Market Price $663.99 You Save 12% ($76.77)
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$587.22

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  • Item 18417
  • MPN# 817460

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    Features, Video & Details

    • Aggressive Flowmaster Super 44 Series Sound
    • Polished Stainless Steel 4" Tips
    • Durable Stainless Steel Construction
    • Includes Two Flowmaster Mufflers
    • Fits 2005-2010 GT, Bullitt and Shelby GT500

    Review & Installation Video

    Review & Install Video

    I’m Justin with AmericanMuscle.com and I’m taking a closer look at Flowmaster’s American Thunder Classic Axle-back exhaust for the 2005-2010 Mustang GT. The classic incorporates the tried and true 40 series muffler, which is the muffler that started it all for Flowmaster many years ago. Now this sound defined Flowmaster and is one of the more aggressive exhausts you can get from their lineup. The classic just like the standard American Thunder incorporates that same 16-gauge aluminized steel for its ability to resist corrosion and its overall durability. Now just like the American Thunder standard, the classic also features that very cool black finish for a stealthy look, however features a slightly larger 4” stainless tip embossed with that very cool Flowmaster logo. Getting the classic bolted up to your Mustang is a very straightforward task, and should take you only about an hour using basic hand tools. Now let’s hear how Flowmaster’s American Thunder Classic sounds compared to your factory exhaust.

    Classic Flowmaster Sound. Give your Mustang that unmistakeable Flowmaster sound with a nice power boost with the American Thunder Axle-Back Exhaust System. This Axle-Back System improves exhaust flow using Flowmaster's patented chambered muffler design for that throaty, aggressive exhaust tone your high powered Pony deserves.

    Quality Construction. Constructed from durable 2.5" 16 gauge stainless steel tubing for its resistance to corrosion, the Flowmaster axle back features two special chambered Super 44 Series Flowmaster mufflers with 4" diameter polished stainless steel tips for muscle car looks and sound. As an added bonus the tip is embossed with the "Flowmaster" logo for true custom styling.

    Application. This Flowmaster American Thunder Axle-Back Exhaust System is designed to fit the 2005-2010 Mustangs including the GT, Bullitt and Shelby GT500 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

    CA Residents: Warning: California's Proposition 65

    What's in the Box
    • (2) Muffler assemblies
    • (2) Clamps
    Installation Info
    Tech Specs
    Axle-Back Exhaust Specifications
    Piping Material: Stainless Steel Tip Material : Polished Stainless Steel
    Piping Size: 2.5" Tip Size: 4"
    Muffler Type: Chambered Fitment: 2005-2010 GT, Bullitt & GT500
    Will it fit my Mustang?

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    Customer Photos (14) Submit Your Photo

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    Questions & Answers (7)

    5 Top Rated Questions

    Will they fit with long tube headers and an x pipe? If not then what full exhaust system do you recommend for a 05 mustang gt.

    • These would fit with long tube headers and an x-pipe but you would need over axle pipes as well to ensure a good fit. We usually recommend cat-back systems for long tube headers and x-pipe modifications to get the most out of your system. We do have the American Thunders in a cat-back system by Flowmaster here: https://www.americanmuscle.com/flowmaster-american-catback-0510gt.html.

    Helpful (0)

    Have stock 07 GT, with Flowmaster Force II kit on it. How does this American Thunder kit compare to Force II Ford Racing FR500s? Want a little more V8 sound, but don't want one that's very loud and annoying to everyone else on the road. Seems like most kits are either too quiet or way too loud. Is there a kit in the middle? Thks!

    • The Flowmaster American Thunder Axle-Back Exhaust will be louder and more aggressive than the Flowmaster Force II and just slightly less aggressive and loud than the FR500S exhaust. The Flowmaster Force II will be the deepest most "muscle car" of the three.

    Helpful (0)

    Does this exhaust fit with the Roush Rear Valance

    • The Flowmaster American Thunder Axle-Back Exhaust is designed to git the 05-10 GT Mustang. The Roush rear valance utilizes a square cut out for squared tips.

    Helpful (0)

    what if you have 3" exhaust coming from headers, do they come in 3" or just 2 a half inch?

    • If your exhaust is 3" but the axle-back exhaust is 2.5" you will need to have it clamped down properly. However I would suggest purchasing an exhaust where the pipe size is 3" because you can be subjected to exhaust leaks or back pressure.

    Helpful (0)

    does this exhaust sound good on an automatic

    • Yes it sure does!

    Helpful (0)
    Post Your Question
    2 More Questions
    How much HP gain will I get with this axle-back exhaust if I already have a BAMA Tune and K&N Air Intake? Also, is this one of the best axle-back exhaust in terms of HP gain? 1 answer
    exhaust So i have a X pipe daul exhaust on my 2008 v6 and i was wandering if i could put the flow master classic thunder gt mufflers on it? 2 answers

    People Who Bought This Item Also Bought

    Customer Reviews (46) Write a Review

    Overall Rating 4.7

    out of 5 stars

    Installation Time:Afternoon

    Installation Cost:0-$100

    • Loudness / Volume 4.425 4.4
    • Exhaust Note 4.75 4.8
    • Fit & Finish 4.4 4.4
    • Bang For Your Buck 4.325 4.3



    • 4/5

      Installation Time: Shop Install

      Installation Cost: 0-$100

      July 24, 2018

      Old school. Sound

      Nice. Sound. For. My. 2008. Mustang. Gt. Reminds. Of. 1967. Mustang. S. Code. Installed. In. One. Hour.

      MarshallW

      Year: 2008 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      June 18, 2018

      Flowmasters Again

      This is my second set of these mufflers. We just bought a 2010 Mustang for my wife and the first thing she had to have were Flowmasters.

      RonD

      Year: 2010 Submodel: GT

      Helpful (3)

    • 4/5

      December 27, 2017

      Flowmaster American Thunder

      I installed this exhaust on my 2010 Shelby GT500. On opening the box, I noticed that one of the tips was welded on slight off center. This was the second Flowmaster kit I purchased with this issue (first kit NOT purchased through American Muscle). I did not return it to American Muscle because, A- not their fault, B- it was not crazy crooked as the first kit was, C- I wanted this exhaust. Installed easy after jacking up back of car and I had to remove both brackets on each muffler to install. On MY car, the Flowmaster tips did not come out as far as stock. My main issue is that the DRONE between 1600ish and 2000 rpm is ridiculous!! Vibrates bit in the car. As my car runs at 1750 rpm at 80 mph, it’s kinda ( read Really Really) loud and distracting. Not figuring in the drone, the exhaust sounds AMAZING during start-up, idle and under acceleration. Tips look great, wish they stuck out another 2 inches. If I could go back in time, I would try the next quieter exhaust kit. I would still stick with Flowmaster, without a doubt.

      StevenM

      Year: 2010 Submodel: GT500

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      November 17, 2017

      Never disappointed

      Sounds like I wanted it too. A little loud for the wife. But I love it.

      Lukes06

      Year: 2006 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      September 21, 2017

      Jeff h

      Very nice sound... some drone, but awesome. Very easy to install.

      JeffH

      Year: 2006 Submodel: GT

      Helpful (2)

    • 5/5

      Installation Time: Less than 1 Hour

      August 23, 2017

      Flowmaster Mufflers

      One of the best sounding mufflers on the market!!! The install was simple. I have Kooks long tube headers with Kooks catted x-pipe and the car sounds amazing with the Flowmaster mufflers!!! I have had many different mufflers on my GT500 and none sound as good as the Flowmaster American Thunder!!!

      EdwardZ

      Year: 2007 Submodel: GT500

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      June 01, 2017

      Sounds Tuff

      Good deep sound. Waiting for mufflers to burn out a little and get louder.

      DonovanW

      Year: 2005 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      April 07, 2017

      Flowmaster AT

      I've had this same axle-back exhaust on three different Mustangs, and they sound great on all. Installation is simple, and the difference is amazing. Only issue I've had is the dreaded drone around 2K rpm. Other than that, they sound great.

      TripleYellowGT

      Year: 2008 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      October 28, 2016

      Flowmasters

      I'll start by saying these flowmasters have an awesome sound. Deep and mean sounding! The kit now includes super 44s vs the classic 40 series mufflers. I was after that classic hollow metallic fox body mustang flowmaster sound and the super 44s just aren't what I'm looking for. They sound more modern with a hint of the classic sound. Drone isn't too bad. Can still talk and hear the radio without issue. Quality is amazing. Look and feel like a great product. Easy install. I still give them a 5 star because they sound great and high quality. I was after a very specific sound and this didn't hit exactly what I wanted but if I hadn't gone in looking for something so specific I would be in love with these. I would say these have a modern mustang, camero, vette, challenger sound to them vs classic fox body.

      MrMustang

      Year: 2007 Submodel: GT

      Helpful (3)

    • 4/5

      Installation Time: Less than 1 Hour

      October 27, 2016

      Love the sound!

      This axle back gives the car a very deep, aggressive tone and sounds great with hot rod cams. That being said, since it has such a deep note, there's a lot of drone at 1500-1900 especially in 5th gear with 3.31 gears. And the exhaust isn't that loud at high RPM either, but that's on a car with stock cats and manifolds. Overall its a good quality, good sounding chambered exhaust. No issues with fitment and the tips look great.

      VaporStang

      Year: 2008 Submodel: GT

      Helpful (3)

    • 5/5

      July 23, 2016

      Great sound, bad packaging

      I received my exhaust on time and in a big box. When I opened it up the exhaust seemed to be in good condition, but the clamp to attach it the the pipes was bent as if it had been crushed. I ended up having to straighten then the clamp because I couldn't use the oem one since it was welded to the other muffler. Took longer than it should because of careless handling. Otherwise the sound is great and at 2k RPM it is amazing.

      Cody

      Year: 2010 Submodel: GT

      Helpful (4)

    • 5/5

      July 15, 2016

      Great upgrade to 05 GT

      Great sound and one of the best mods you can do yourself in under two hours. Great perfomance gains. Not to loud like other have said. American Muscle is the best they are spot on in descriptions and videos. I am running an 05 GT with Air Aid cold air intake, new Flowmasters and Bama performance custom tune. Great buy! worth the money..

      DREW

      Year: 2005 Submodel: GT

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      June 24, 2016

      Simple upgrade to enhance the tone of any Stang

      With simple hand tools, this install took me about an hour to complete. Easy bolt-on...excellent fit...and very nice exhaust tome as a result. Highly recommended.

      Locogeronimo

      Year: 2008 Submodel: GT500

      Helpful (3)

    • 5/5

      Installation Time: Afternoon

      May 14, 2016

      Be careful what you ask for

      My stock 05 gt cruised around town with hardly a second glance. Since I added these it rumbles and roars at every vehicle it sees and attracts much attention.... Some of it good.. Some of it bad. These will definitely get you noticed. Some people seem to appreciate the old school muscle car sound while others take it like a middle finger sticking out a window. Expect many people to challenge you...just be prepared because these change everything.

      Giffy

      Year: 2005 Submodel: GT

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      May 11, 2016

      American Thunder Classic

      Love this exhaust, sounds great with great volume. Only problem i had with it was that I have Pypes' Dual Exhaust Conversion Kit for V6 Mustangs and since the products are from different companies, the metal hangers coming off the muffler are a little short and therefore it was very hard to make the mufflers line up and mine are kind of touching my bumper too so im a little worried about it melting

      Bill

      Year: 2009 Submodel: V6

      Helpful (4)

    • 5/5

      Installation Time: Afternoon

      August 18, 2015

      The Drone Goes Away

      Installing these wasn't as bad as I thought it was going to be. One of the hangers bolts just happened to be in between the frame and the muffler on the left side so there was only an inch or two of room to fit a wrench in. (I cursed myself for not purchasing ratchet wrenches) I have a 2008 Mustang GT so I'm not sure if this is the case on other year models but one of my exhaust hanger brackets had some sort of metal bracket welded to it that none of the others had, along with an extra bolt to hold it up there. So word of advice, don't go pulling on the old muffler until you have undone that "hidden" bolt or else you will bend that hanger. After that it was smooth sailing, the Flowmasters lined up very well on the first try and I didn't have to go back and mess with the alignment. The big moment when you crawl out from under there and jump into the drivers seat to turn it over for the first time was very memorable for me. Instant smile. These Flowmasters sound fantastic, they have a low booming tone in the lower RPMs but man when you get up to the high end the thing screams! I find myself leaving the door open when I start the car up now just to hear them as well as driving with the windows down. There was a definite drone around 55mph in 5th gear for me, VERY loud and deafening. It has gone away now that I have driven with them on my car for about a month, thank god.

      Zakk

      Year: 2008 Submodel: GT Kentucky

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      March 25, 2015

      Awesome upgrade!

      This was my first Flowmaster purchase and it did not disappoint! The part number was 817460. These mufflers make the the 2010 GT mustang sound like it should! Very impressive exhaust note. Cold start in the garage vibrates the walls! My 2010 Mustang GT has a manual transmission and these mufflers are a lot of fun! Love revving it up at stop lights or in traffic, definitely turns heads. At W.O.T. the car sounds like a jet. These mufflers do vibrate the car at idle! Feel them in the floorboards and the pedals! Reminds me of a '69 Mustang with a 351c. They have a strong exhaust note between 1800 to 2300 R.P.M. especially on the freeway! If you like it loud then these mufflers are for you! Install was super simple! If you can change a tire you can put these in! Took us less than an hour. OK now the cons. Since these are designed for 2005 to 2010 Mustang GT, the tip placement was more inboard and not centered in the cutouts on my 2010 GT. Not enough to bother me but it mite be a problem for others. Their is not enough adjustment in the factory brackets to get the to fit perfectly centered, at least on my car. Like I said earlier in the review they have a heavy exhaust note or drone between 1800 to 2300 R.P.M. At first it was really annoying but now I love it! To finish. I love them! Highly recommended! If you like it loud, obnoxious, head turning, popping and vibrating then these are the mufflers for you! Between my 2010 Mustang GT and these mufflers makes me feel like a kid again! Buy them you will not be disappointed!

      avmotorsports

      Year: 2010 Submodel: GT Yakima, WA

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      December 21, 2014

      It sounds like a classic muscle car

      I looked a long,long time at different cat-back systems by all manufacturers. Listened to dozens of audio and video clips and chose the Flowmasters because I was looking for that classic sound. The clips did not do capture the sound as much as hearing them in person. After the installation, the start up was awesome!!!! This was what I wanted!!

      Racerbob

      Year: 2009 Submodel: GT Troutdale, OR, USA

      Helpful (2)

    • 5/5

      Installation Time: Afternoon

      July 17, 2014

      The sound is amazing!

      I listened to many--many audio clips. You will not be disappointed. A full and deep tone and the neighbors won't hate you. Some drone between 60 and 70 mph but it's not bad and disappears over 70. After removing the old muffler, loosen the forward bracket on the drivers side and tighten after installation. This step would have saved us a lot of time. I am extremely happy with this purchase for my 2010 GT.

      KCPony77

      Year: 2010 Submodel: GT Olathe, KS, USA

      Helpful (3)

    • 5/5

      Installation Time: Less than 1 Hour

      April 13, 2014

      Great Exhaust

      Exhaust sounds great. Install is extremely easy once the factory exhaust has been removed. Highly recommend this product!

      Bquart

      Year: 2010 Submodel: GT Joplin, MO, USA

      Helpful (3)

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