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Flowmaster Force II Axle-Back Exhaust; Aluminized Steel (05-10 GT, GT500)

Item 18403
Market Price $507.99 You Save 12% ($59.04)
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$448.95 (pair)

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      Review & Installation 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.

      Product Information

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


      • Aggressive Flowmaster 60-Series Delta Flow Sound.
      • Polished Stainless Steel 4" Tips.
      • Durable Aluminized Steel Construction.
      • Includes Two Flowmaster Mufflers
      • Fits 2005-2010 GT and 2007-2010 Shelby GT500 Mustangs.


      Flowmaster Sound. The Flowmaster Force II Axle Back exhaust system, with it's patented 60 Series Delta Flow chambered mufflers will improve your GT or GT500 Mustang 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 Force II 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 aluminized steel Flowmaster Force II 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

      MPN# 17410

      CA Residents: WARNING: Cancer and Reproductive Harm -


      Customer Reviews (100+)

      Write a Review

      Ratings Summary

      4.7 out of 5 overall rating from 100+ customers

      Installation Time: Afternoon

      Installation Cost: 0-$100

      • February 19, 2019

        5 2010 GT - KrisN Installation Time: Afternoon

        Nice sound over stock mufflers

        Good mufflers if you want a little better growl than stock mufflers. Not to loud as too annoy the neighbors but loud enough to let everyone know you have a V8 under the hood.

        Helpful (1)
      • October 14, 2018

        1 2008 GT - GlennT Installation Time: Shop Install Installation Cost: $100-$250

        Not what I expected at all......

        Got the axel back force 11 exhaust in and had set up appointment for them to be installed , got old magnaflows off and the flowmasters that were supposed to fit my car would not fit, instead of offset they sent straight out the middle, so I'm stuck with my car on the rack and the wrong mufflers, being I was being charged by the hour I had him make adjustments to fit, costing me more $$$, Noise level was the same as I had on the car with the Magnaflows,

        Helpful (5)
      • July 20, 2018

        3 2008 GT500 - Gus Installation Time: Less than 1 Hour

        Flowmaster Force II Axle-Back Exhaust

        Video reviews are subjective. I was looking for more loudness over stock pipes, not crazy outlaw sound, which I love and have on my GT but more aggressive than stock pipes. These are built very well and look great but not much louder than stock pipes. The exhaust sound is deep, not raspy, just wish they were a little louder.

        Helpful (5)
      • June 26, 2018

        4 2006 GT - aidenshep Installation Time: Afternoon

        Louder then I thought

        The exhaust tone is ok no drone. However they are louder then there rating. They are a lot louder then stock mufflers. I was looking for a compromise between stock and aggressive sounding . These are not .... Fit and finish is very good....

        Helpful (7)
      • May 22, 2018

        5 2007 GT - AlexV Installation Time: Less than 1 Hour

        Way better

        Much better than what I had on the car little louder than right up with stock hangers. Much better exhaust note.

        Helpful (8)
      • April 17, 2018

        5 2010 GT - LaurenceM

        2010 GT Mustang 4.6l

        HotRod Cams Kooks long tube headers 62mm throttle body Cold Air Intake Steeda pullies Sounds great with no drone!

        Helpful (11)
      • January 06, 2018

        5 2007 GT - WalterC Installation Time: Shop Install Installation Cost: 0-$100

        Performance without the loudness

        I was looking to install some performance mufflers that would be as quiet as possible . I was not expecting it to be the low humm that it is at idle. But the noticeable difference when you step on it without being annoying.Perfect sound for me sounds nice and and you definitely feel the difference.

        Helpful (9)
      • December 08, 2017

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

        sounds great

        I have 2006 Gt with K and N intake 3.73 gears pypes off road X and now these flowmasters sound great. easy install car can be quiet but when you hit the gas it’s s deep loud rumble that sounds very good.I love setting off car alarms.

        Helpful (8)
      • October 17, 2017

        5 2007 GT500 - RichC Installation Time: Shop Install Installation Cost: $100-$250

        Check size before you buy

        If you are buying a car where you know nothing of it's history, it would be wise to get under there and check what is there. I assumed it was factory and it wasn't' so I had to take it to a muffler shop instead of being able to mount them myself. Otherwise, these provide justtt the right amount of tone, loudness and note that I was looking for. And are quiet enough that I can now hear my supercharger whine. Previous owner had very loud almost straight pipes on it. The exhaust videos of how the different axle backs sound was a great help in my choosing these. If your an older guy (mid 50's) like I amI think you would be pleased with the sound.

        Helpful (9)
      • August 10, 2016

        4 2006 GT - Zeb

        Awesome, but not what I thought it was

        Fairly easy install with a friend helping. Sounds great from outside the car and with the windows down. Only problem was I ordered these because I drove a 07 GT/CS that had them and it sounded sick, turns out I guess that one had the whole cat back system with the X pipe, because this one sounds just like it from the outside, but the other I drove had MUCH more drone in the cabin. Which I loved. Hopefully I can add the X pipe in at a later date and get that sound. All in all happy, but I think I was looking for the full system.

        Helpful (7)

      Questions & Answers (14 answers)

      5 Top Rated Questions

      Does the Force II have a drone type noise in it. I tried other makers and got a bad drone at 2000 RPM's and driving at 55 MPH the legal speed limit here. The drone is the reason I went back to stock and I would sure like to enhance the current sound.

      • The Flowmaster Force II Axle-Back Exhaust will feature some drone at certain RPMs.

      Helpful (1)

      will this work? if i convert my v6 07 mustang to the duel exaust will these work/will any other GT mufflers work?

      • yes

      Helpful (1) Show 1 more answer

      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.

      Helpful (1) Show 1 more answer

      what are the DB's on this exhaust?

      • Exhast Decibel level is not listed for any of the exhausts we offer, as this can vary from car to car and change based on the rest of your setup.

      Helpful (0)

      Are these mufflers available individually anywhere? I only need the right side muffler

      • The Flowmaster Force II Axle-Back Exhaust is only sold as a kit. We do not sell the mufflers individually.

      Helpful (0)
      Post Your Question
      9 More Questions
      How does the aluminized steel hold up to high temps? I have an 08 with long tube headers and no cats. I have the black pype bombs on now, and the powder coating is flaking off due to excessive exhaust temps. 1 answer
      Do I have to buy the hanger kit or can I use my stock hangers and save the cash? Thanks. 1 answer
      Hi everyone! I am kind of confused because of the product information. The price says €380.12 for me (each). Does "each" mean left and right in each case €380.12 or does "each" mean the complete muffler-system (including both)? Because further down it says both mufflers are in the box. Kind regards gzunlimited 1 answer
      Does this exhaust sound good on an automatic (05-10 GT) ? 1 answer
      Will these fit on an 08 GT CS? 2 answers
      Does it add any power or torque 2 answers
      What is the change in noise level within the car? 3 answers
      is this loud when going about 25 or 30mph 5 answers
      Wondering is this available for shipping to Canada? Toronto specifically. Wondering is this available for shipping to Canada? Toronto specifically. 2 answers

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (1) Right muffler assembly
      • (1) Left muffler assembly
      • (2) Clamps
      • (1) Nut
      • (1) Lock Washer

      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:ChamberedFitment:05-10 GT, GT500 Mustangs

      Will It Fit My Mustang

      • Bullitt - 08, 09
      • GT - 05, 06, 07, 08, 09, 10
      • GT500 - 07, 08, 09, 10

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