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

100+ Reviews
Our Price


  • Item #18403
  • MPN# 17410

  • Market Price $475.70
  • You Save 12% ($54.73)
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Product Videos Customer Photos
  • Aggressive Flowmaster 60-Series Delta Flow Sound.
  • Polished Stainless Steel 4" Tips.
  • Durable Aluminized Steel Construction.
  • Includes Two Flowmaster Mufflers
  • Fits 05-10 GT and 07-10 Shelby GT500 Mustangs.

Flowmaster Sound. The Flowmaster American Thunder axle back exhaust system, with it's patented 60 Series Delta Flow chambered mufflers will improve your Mustangs exhaust flow for an increase in power and a throatier exhaust note.

Quality Construction. Constructed from durable 2.5" 16 gauge aluminized steel tubing for it's corrosion resistant properties the Flowmaster axle back features specialty 5" X 10" chambered 60 Series Delta Flow American Thunder mufflers with massive 4.0" diameter polished stainless steel tips for muscle car looks and sound. As an added bonus the tips are embossed with the "Flowmaster" logo for true custom styling.

Fitment. This Flowmaster American Thunder Axle-Back exhaust system is designed to fit the 2005-2010 GT 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
  • (1) Right muffler assembly
  • (1) Left muffler assembly
  • (2) Clamps
  • (1) Nut
  • (1) Lock Washer
Installation Info
Tech Specs
Axle-Back Exhaust Specifications
Piping Material: Aluminized Steel Tip Material : Polished Stainless Steel
Piping Size: 2.5" Tip Size: 4.0"
Muffler Type: Chambered Fitment: 05-10 GT and 07-10 Shelby GT500 Mustangs
Will it fit my Mustang?
  • Bullitt - 08, 09
  • GT - 05, 06, 07, 08, 09, 10
  • GT500 - 07, 08, 09, 10

Most Helpful Reviews

Boo price drop

I bought these for christmas. Went on fairly easy, passenger hangs a little low but so did my stock exhaust, its just a little more noticeable with the huge tips. have put almost 1000 miles on them and ...

Read More
Helpful (1)

09 Mustang GT

Lots of droning at first. needs about 1 month to fully break in. Recommend welding arounf the clamps to keep water out, and ensure good seal. Otherwise real easy install and sounds real good.

Helpful (3)

Overall Rating 4.7 out of 5 stars
Read All 100+ Reviews

Review & Install Video

I’m Justin with, and this is our detailed breakdown of Flowmaster’s American thunder series Axle-back for the 2005-2010 Mustang GT. This kit from Flowmaster centers around those patented classic 60 series delta mufflers that are responsible for that iconic Flowmaster muscle car sound and rumble. Flowmaster is one of the only companies that chooses to use 16-gauge aluminized steel for their exhaust versus stainless steel. Now that coated steel is going to be great for resisting corrosion, and that sleek black finish is going to look really sharp underneath the rear bumper. Now the entire kit is finished off with these dual 4” tips and embossed with that iconic Flowmaster logo. Getting the American Thunder bolted up to your ride is a very straightforward task that should take you no more than an hour using some basic hand tools. Now let’s see how Flowmaster’s American Thunder sounds compared to our factory exhaust.

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10 Questions / 9 Answers

Ask a Question

Wondering is this available for shipping to Canada? Toronto specifically. Wondering is this available for shipping to Canada? Toronto specifically.


  • Sure thing! We can ship this to Toronto. If you want to get a quote on shipping, feel free to give us a call or use the shipping calculator once the exhaust is added to your shopping cart!


    Good Answer (0) (0)

Show 1 more answer Question Resolved

Will this work? Can i use these axle back exhaust on my 05 v6 mustang if i purchase the pypes x pipe?


  • The short answer is no. I would suggest buying a V6 True Dual Exhaust conversion kit. That way you get all the parts necessary for converting your entire exhaust system.


    Good Answer (2) (2)

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

is this loud when going about 25 or 30mph


  • YES! I was shocked by how loud it is, after break in you will be pleased


    Good Answer (3) (0)

Show 4 more answers Question Resolved

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Customer Reviews (100+) Write a Review

Overall Rating 4.7

out of 5 stars

Installation Time:Afternoon

Installation Cost:0-$100

  • Loudness / Volume 4.1875 4.2
  • Exhaust Note 4.594594 4.6
  • Fit & Finish 4.473214 4.5
  • Bang For Your Buck 4.594594 4.6

  • 5/5

    January 23, 2011

    Boo price drop

    I bought these for christmas. Went on fairly easy, passenger hangs a little low but so did my stock exhaust, its just a little more noticeable with the huge tips. have put almost 1000 miles on them and they are really starting to sound sweet. The price dropped almost $50 the week after I bought them which sucks but... I am pleased thought they weren't going to be loud enough at first, sounds great but not really loud. Third gear pulls harder than it did before which is nice.... Slight issue with leaks around the clamps provided by Flowmaster, stock clamps wouldn't come off original axle-backs. Overall, great product, if you are looking for something to give your stang a little more kick and a more throaty sound with out sounding ragged out these are the ones.


    Driving Style: Daily Driver

    Helpful (1) (0)

  • 4/5

    August 02, 2009

    09 Mustang GT

    Lots of droning at first. needs about 1 month to fully break in. Recommend welding arounf the clamps to keep water out, and ensure good seal. Otherwise real easy install and sounds real good.


    Year: 2009 Model: GT

    Helpful (3) (0)

  • 5/5

    June 18, 2010

    Good Sound

    Very nice product, produces just enough sound to give a nice rumble and not tick off the nieghbors. Excellent fit and the large tips look great coming out the back.


    Helpful (37) (3)

  • 5/5

    November 20, 2010


    Love the Flowmasters. Installed myself in about 1.5 hours without a jack in my apartment garage. Hardest part was removing the stock mufflers. Great sound but initial drone made me nervous that I had made the wrong decision. After about a month the drone has gone away and the exhaust sounds more muscular. Nice and quiet when cruising down the highway, but growls when you get on the gas. Great combination for every day driving. Would recommend to everyone. This is how they should have came stock!


    Driving Style: Daily Driver

    Helpful (25) (1)

  • 5/5

    April 06, 2010

    Buy This

    I recently put this system on an 07 GT. The only minor problem i had was that the end of the pipe on the inlet of the new mufflers was slightly out of shape. Easily fixed with a little hammering. Aside from that, easy install, fits perfect. Sounds perfect!!! Much like my opinion of the cars style, this system sounds like a perfect blend of muscle car and new car. It's loud when you want it to be, but you can keep it pretty quiet if you want to hear the radio or are driving through town. I definitely recommend this over competitors, the price is hard to be as well


    Year: 2007 Model: GT

    Helpful (14) (2)

  • 4/5

    March 16, 2010

    Sounds Amazing

    I installed these on my 2010 and my buddy's 2007 and they sound great. The installation was fairly quick and they fit like a glove. One of the mufflers came with the inlet hammered up (probably due to shipping) so we had to fix that. I was also happy to discover that there is no "droning" with these mufflers, I was afraid they would. You can't beat the sound of these mufflers for the price you pay.

    Johnny Pounder

    Year: 2010

    Helpful (14) (2)

  • 4/5

    June 30, 2009


    its about time they carried flowmasters!!! freakin love them... a little droning in the beginning aroud 2100 grand... after they get broke in, they\'re AMAZING!!!


    Helpful (16) (3)

  • 5/5

    May 23, 2011


    After much debate and sound clips I chose the American Thunder. I was originally going with the Borla Stinger S-Type, but had a hard time justifying that coin for a couple mufflers. Got an email from American Muscle....$269 I took a gamble on a bargain and I can honestly say this is one of those times the bargain actually pays off! At idle it is slightly louder than stock with a much deeper tone. Ease off the clutch and it comes to life with a mellow growl. At full throttle it sounds like a muscle car, and anyone who has been behind it compliments me on the sound. Highway mode is awesome, it is equally if not more quiet than stock. If you want it to sound great when on the gas but not drone your brains out this is the system for you. I only have the axleback and have no plans to change. If you want everyone to stare at you and dont mind it sounding like a ricer go with something else...and please sell your mustang.


    Year: 2005 Model: GT Driving Style: Daily Driver

    Helpful (23) (7)

  • 5/5

    August 20, 2010


    I have a 2010 mustang gt, I ordered this thinking that it would mot make much of a difference, well i was very wrong. The sound is a night and day difference from the stock exhaust. The sound is just strong feeling, there are no words that can decribe on how happy i im with this.

    Justin N

    Year: 2010 Model: GT

    Helpful (21) (6)

  • 5/5

    January 12, 2011

    Flowmaster Axle-Back

    Awesome product! Having a ramps, lift, or jack would definitely help with install. Some suggestions though if you go with these go buy high temp paint and paint them up before you install them, the black finish flakes off super easy. Second thing, if you can take the stock clamps off if you can. The supplies clamps don't seem to tighten down as much as the stock ones do. Overall the Flowmasters sound awesome though and I would definitely recommend.


    Driving Style: Daily Driver

    Helpful (9) (1)

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