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Flowmaster American Thunder Axle-Back Exhaust (15-17 GT)

Item 384452
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      Video Review & Installation

      Hey, everybody. Justin with here, taking a quick look at the American Thunder Axle-Back from Flowmaster fitting your 2015 Ford Mustang GT.Flowmaster is, without a doubt, one of the most recognizable names in the Mustang world, and it has been the hot rodders' choice for many decades. Now, we've used several of their products in some of our past builds, including the recent BAMA Terminator. If you guys haven't seen these builds yet, what are you waiting for? Be sure to check out some of our project car builds in addition to the best Mustang specific content on the web by checking out our YouTube Channel, American Muscle videos.So the American Thunder from Flowmaster is one of those tried and true systems that sounds killer on just about every generation Mustang, including the new 2015 Coyote powered Ford Mustang GT. Now, that iconic sound comes courtesy of the Super 44 Series mufflers here which will give your S550 just a little bit more bark, but won't wake the neighbors in the process. The entire system has been constructed from durable 409 grade stainless steel and features this durable high-temp black coating here, which should help reduce any corrosion over the years. Piping is all 2-1/2 inch mandrel bent, and we're looking at 4-inch slash cut tips embossed with that iconic Flowmaster logo.Now, guys, if I haven't answered every single one of your questions about the American Thunder here and you'd like to see more detailed information along with some detailed install tips, then be sure to check out the product page at if you haven't already done so.As you may or may not have heard by now, installing an Axle-Back onto your 2015 Mustang will require some cutting, as is the case here with the Flowmaster American Thunder. But don't worry. As long as you take your time, follow the detailed instructions, you should have no problems knocking it out in about an hour from start to finish.Either way, guys, if you do have any more questions about the exhaust or about the actual install, feel free to reach out to one of our Mustang experts any time using the 1-800 number. They're always standing by, ready to help a fellow Mustang owner in need.Now, it's time to hear how the Flowmaster American Thunder Axle-Back sounds compared to the factory exhaust.

      Product Information

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


      • Aggressive Flowmaster Super 44 Series Sound
      • Durable 409 Stainless Steel Construction
      • 2.5" Mandrel-Bent Tubing
      • 4" Polished 304 Stainless Steel Tips
      • Includes (2) Flowmaster Super 44 Series Mufflers
      • Compatible with Fastback and Convertible
      • Fits All 2015-2017 GT Mustangs


      Classic Flowmaster Sound. Add the unmistakable Flowmaster sound to your S550 GT with an American Thunder Series Axle-Back Exhaust System from AmericanMuscle. This axle-back system improves exhaust flow using Flowmaster's Super 44 Series mufflers for that classic aggressive muscle car exhaust note your high powered Pony deserves.

      Stainless Steel Construction. Constructed from durable 2.5" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties, the Flowmaster American Thunder Axle-Back features Super 44 Series mufflers with massive 4.0" diameter polished 304 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.

      Cut & Clamp Installation. The installation of this Axle-Back Exhaust requires cutting and removing the factory muffler assemblies and clamping the new muffler assemblies in place. Clamps and instructions are provided.

      Application. This Flowmaster American Thunder Series Axle-Back Exhaust System is designed to fit the 2015-2017 GT Mustangs, including fastback and convertible models.



      Flowmaster 817749

      CA Residents: WARNING: Cancer and Reproductive Harm -

      Installation & What's in the Box

      Installation Info

      What's in the Box

      • (2) Muffler assemblies

      Tech Specs

      Axle-Back Exhaust Specifications
      Piping Material:409 Stainless Steel Tip Material :Polished 304 Stainless Steel
      Piping Size:2.5"Tip Size:4"
      Muffler Type:ChamberedFitment:2015-2017 GT

      Customer Reviews (100+)

        Questions & Answers

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        Will It Fit My Mustang

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