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2018-20 Mustang Flowmaster American Thunder Axle Back Exhaust - w/o Active Exhaust GT by Flowmaster

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  • 817807 2018 MUSTANG GT FLOWMAS
  • 817807 2018 MUSTANG GT FLOWMAS
  • 817807 2018 MUSTANG GT FLOWMAS
  • 817807 2018 MUSTANG GT FLOWMAS

Increase the sound and performance of your Mustang with this 2018-20 Mustang GT American Thunder Series axle back exhaust kit from Flowmaster!

Item #FLO-817807
MPN# 817807

Everyday Low Price: $725.95

  Ships from supplier by Friday, November 06

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  • Increases Horsepower & Torque
  • Replaces Factory Axle Back
  • Easy Installation
  • Made In USA


  • Super 44 Series Mufflers
  • 409S Stainless Steel Construction
  • 3" Mandrel Bent Tubing
  • 4" Polished Tips

What's in the Box

  • (1) RH Axle Back Muffler w/ Tips
  • (1) LH Axle Back Muffler w/ Tips
  • (2) Exhaust Clamps

Flowmaster Brand Image

Product Description

Mustang GT American Thunder Axle Back
Flowmaster has done it again with this 2018-2020 Mustang GT American Thunder Series axle back exhaust system. Bolt on this performance axle back to your Mustang to hear and feel an increase in horsepower and sound! This axle back minimizes the restrictions that the factory axle back has, maximizing the exhaust flow for an increase in fuel economy and throttle response as well! This axle back is made to fit on all 2018-2020 Mustang GT's that did not come with the active performance exhaust option from the factory. Pick up the classic Flowmaster sound for your 2018-2020 Mustang GT and start turning heads everywhere you go!

Flowmaster Quality
Featuring 3" fully mandrel bent 409 stainless steel tubing, this axle back kit packs a mean rumble with this system ending at their well-known American Thunder series mufflers and finished off by huge 4" polished stainless steel quad tips! This kit comes backed by Flowmaster's lifetime warranty to give you peace of mind. Designed and made right here in the USA for a problem-free fit, these systems include all necessary clamps along with detailed instructions for a simple installation.

Installation Note
This axle back does NOT fit Mustangs with the active performance exhaust option.

-Fits 2018-2020 Mustang GT

Flowmaster Exhaust Warranty - Click Here

California Residents:
WARNING: Cancer and Reproductive Harm- www.P65Warnings.ca.gov

Product Videos

Flowmaster American Thunder Axle-back Exhaust for 2018-2019 Ford Mustang GT 5.0L - Part # 817807

Check out our YouTube channel for even more tech tips, installation videos, how-tos, and more. The best place to go for anything Mustang related!

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Vehicle Applications

Ford Mustang - 2018 (18)

About This Brand

Flowmaster - The Exhaust Technology Company
Flowmaster operates the only exhaust Research & Design facilities of its kind in the world, centered around the SuperFlow SF-7100 engine dynamometer complete with E.C.A. (engine cycle analysis) equipment and also SuperFlow chassis dyno's.

Through use of these dyno's, Flowmaster's engineering staff can track the complete engine cycle in millionths of a second and can obtain exact technical data of each degree of cam rotation, from induction to the tip of the exhaust system, while also showing the power numbers that really matter, the power numbers "to the ground."

Flowmaster also utilizes Spectrum Analyzers to fine "tune" the sound of each of the eleven different series of mufflers that Flowmaster currently offers, both for peak performance and just the right sound levels and tones. Flowmaster's dedication to quality is what makes them the exhaust industry leader for Latemodel Mustangs and SVT Lightnings!

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