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Flowmaster American Thunder Cat-Back Exhaust (11-12 GT)

Item 18428
AmericanMuscle no longer carries the Flowmaster American Thunder Cat-Back Exhaust (11-12 GT). Please check out 2015-2022 Mustang Cat-Back Exhaust for an updated selection.
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    Video Review & Installation

    Hey I’m Justin with, and I have with me FlowMaster’s American Thunder series Cat-back exhaust fitting all 2011 and newer Mustang GTs. The thunder you get from using this system comes from Flowmaster’s 60 series delta flow mufflers, which will still give you that classic muscle car sound, but will still be a bit milder than Flowmaster’s Outlaw series, or their Force 2 exhaust, which utilizes a more aggressive 40 series muffler. The American Thunder is a true cat back exhaust, meaning it eliminates your factory H-pipe utilizing 3” mandrel bent tubing all the way up to your factory cats. One thing we noticed with our mid pipe is it features a mini crossover, just to equalize your exhaust flow. Everything exits out these 60 series delta mufflers, and out these dual 4” hand polished tips. Getting the American Thunder bolted onto your ride is a straight forward affair which should take you no more than 2 hours using standard hand tools. Now let’s hear how Flowmaster’s American Thunder sounds compared to our factory exhaust.

    Product Information

    Features, Description, Q&A, Specs & Installation


    • Aggressive Flowmaster 60-Series Delta Flow Sound
    • Durable 409 Stainless Steel Construction
    • 3" Mandrel-Bent Tubing
    • 4" Polished Stainless Steel Tips
    • Includes Two Flowmaster 60 Series Mufflers
    • Fits 2011-2012 GT


    Signature Flowmaster Sound. Give your coyote Mustang that unmistakeable Flowmaster sound with the American Thunder Cat-Back Exhaust system from AmericanMuscle. The Flowmaster American Thunder Cat-Back Exhaust with its mandrel bent tubing will greatly improve your Mustangs exhaust flow for an increase in power, and the included 60 Series Delta Flow Mufflers will improve your exhausts sound for a deep aggressive muscle car exhaust note.

    Reuses Stock Cats. The included Flowmaster Scavenger X-Pipe bolts up directly behind the factory catalytic converters with no cutting required saving you time and money. By reusing your stock catalytic converters, you ensure that your Mustang is smog-legal.

    Quality Construction. Constructed from durable 3" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties the Flowmaster American Thunder Cat-Back features two 60 Series Delta Flow American Thunder 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 American Thunder Cat-Back exhaust system is designed to fit the 2011 to 2012 5.0L coyote Powered GT Mustangs equipped with either aftermarket shorty headers or the factory manifolds. Does not fit Shelby GT500 models.

    CA Residents: WARNING: Cancer and Reproductive Harm -

    Installation & What's in the Box

    Installation Info

    What's in the Box

    • (2) Muffler Assemblies
    • (2) Over Axle Pipes
    • (4) Clamps

    Tech Specs

    Axle-Back Exhaust Specifications
    Piping Material: 409 Stainless Steel Tip Material : Polished Stainless Steel
    Piping Size: 3.0" Tip Size: 4.0"
    Muffler Type: Chambered Fitment: 2011-2012 GT

    Questions & Answers

    10 More Questions

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