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Flowmaster Exhaust Systems Flowmaster American Thunder Cat Back Exhaust System - 817730

2,155 Reviews
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  • Part #: 817730
  • Main piping diameter: 3"
  • 60 Series Muffler
  • Includes dual 4" polished exhaust tips
  • 2015 - 2017 Ford Mustang GT, 5.0L, V8, Fastback/Hardtop Only, Cat-back, 3.00" Mandrel Bent Tubing, Dual System, 60 Series Mufflers, 4.00" Polished Tips, American Thunder, DOR, 409S Stainless Steel.
  • American Thunder Cat Back Exhaust System, Dual, Dual Out Rear Exit, Incl. 3.0 in. Tubing/60 Series™ Mufflers, 409 Stainless Steel
  • Mandrel Bent 16ga 409 Stainless Tubing, Aggressive Exterior Exhaust Tone, Incl. Hangers and Hardware For Easy Installation, Dyno Tuned for Maximum Performance, Premium Flowmaster Quality, Patented Delta Flow Technology, Lifetime Limited Warranty, Made in the USA
  • Download installation instructions (PDF)
  • With Dual Exhaust Tips
  • Dual Rear Exit (409 Stainless)
Ships by 03/22/2023
Have a Question? Ask a product expert!
Have a Question? Ask a product expert!




Product Info
  • Choose from up to four signature Flowmaster Exhaust series (depending on your vehicle):
  • Outlaw Series: Flowmaster’s most aggressive, race-oriented system perfect for drivers seeking loud sound levels
  • American Thunder: The sound that started it all, with Flowmaster’s original sound levels and performance
  • FlowFX: A moderate tone but without that "chambered" sound, this system still provides all that Flowmaster performance.
  • dBX Flowmaster: Perfect for smaller displacement four- and six-cylinder engines and can be used in both imported and domestic cars and trucks
  • Force II: Features a mild, chambered muffler tone for drivers seeking performance gains with quieter sounds
  • Custom-crafted for your specific year, make and model vehicle
  • Large-diameter mandrel-bent pipes deliver a restriction-free exhaust flow
  • Each kit is powered by Flowmaster's legendary high-performance mufflers
  • Available with single, dual, rear and side exit configurations (depending on your vehicle)
  • You have your choice of aluminized or stainless steel construction (depending on the kit)
  • Includes tubes, mufflers, tips, clamps, hardware & hangers and installation instructions (varies by kit)
  • Stainless steel systems are backed by a limited lifetime warranty
  • Aluminized steel systems are backed by a 3-year warranty
  • Flowmaster Exhaust is proudly made in the USA

The Flowmaster Exhaust System delivers more than a little sound and power – enjoy impressive horsepower gains, a handy boost in MPG, and the most famous exhaust tone in the automotive world. Not to mention, each Flowmaster Exhaust System is custom-bent from aluminized or stainless steel to fit your specific year, make and model.

Flowmaster has a wide range of different systems for you to choose from. If you want an all-out, loud exhaust system, go with the American Thunder. The Outlaw Series is an aggressive, race-oriented system and almost as loud. The FlowFX series has all that Flowmaster performance with a moderate tone. Sport compacts, imports and Euro machines sound off with the dBX Series, and, for wicked performance with a mild tone, the Flowmaster Force II System is best. Have your pick of single, dual, side and rear exits (depending on the model). Each kit is powered by performance mufflers and comes with all the parts you need for a quick install.

Your Flowmaster Exhaust System is backed by different warranties, depending on the materials used – for aluminized steel, you’re looking at a 3-year warranty, and for stainless steel, there’s a limited lifetime warranty.



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  • ATTN: State of California Consumers
    warning symbolWARNING: This product can expose you to chemicals including nickel (metallic) and chromium (hexavalent compounds) which are known to the State of California to cause cancer and birth defects, or other reproductive harm (For more information go to www.p65warnings.ca.gov)
Moss Warranty Act Statement

Thanks to the Magnuson Moss Warranty Act: US Code – Title 15, Chapter 50, Sections 2301-2312, your vehicle’s factory warranty is protected by law when you add aftermarket parts.

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Customer Reviews

Average Rating
Ease of Installation
2155 Customer Reviews
5 Star
1507 (70%)
4 Star
517 (24%)
3 Star
83 (4%)
2 Star
30 (1%)
1 Star
18 (1%)

This exhaust is PERFECT!!

I did complete this install at home and had no help, so it was a little more work than anticipated. The work totally paid off upon start up. Looks great, sounds magnificent!!!I can say this was the best purchase I've made in a while.
Ease of Installation
Posted By Anthony G (macon, GA) / November 2, 2017
2017 Ford Mustang
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