The Sound That Started it All

American Thunder® is the ‘original’ Flowmaster sound. In most cases a very aggressive sound level, American Thunder systems use various chambered mufflers to achieve the performance gains and aggressive sound that you want from your car or truck, inside and out. Available in stainless steel or economical aluminized steel, American Thunder systems are a great choice when you want to be heard.


  • Aggressive Sound Exhaust Tone
  • Mandrel Bent 16 Gauge Tubing
  • Axle-Back, Cat-Back, or Header-Back Systems
  • Includes Hangers and Hardware for Easy Installation
  • Dyno Tuned for Maximum Performance