Flowmaster American Thunder Exhaust Systems add a signature growl that's best described as the "Flowmaster Sound" - A muscular, throaty rumble that announces your engine's presence. Flowmaster is the true tone of classic American muscle and performance.
Fits 99-04 GT And 03-04 MACH 1 Will Not Fit Vehicles Equipped With IRS
3 Year Warranty
What's in the Box
(2) Muffler Assemblies With Flow Tubes
(2) Tailpipes with Stainless Steel Tips
(2) Exhaust Clamps
For the person who is looking for a complete cat-back dual exhaust system with an aggressive tone for their 1999-04 Mustang GT, this is the kit to have. With easy fit in mind, these American Thunder systems from Flowmaster are mandrel bent for maximum performance and include specially selected mufflers. American Thunder systems deliver a moderate to aggressive interior and exterior tone and are suited to the enthusiast who wants their performance to be heard. Like all Flowmaster systems, the American Thunder benefits include improved throttle response, power and mileage. Designed for an easy fit, these Mustang exhaust systems include all necessary parts and hardware for easy installation.
Since Flowmaster mufflers use sound energy cancellation technology, you don't have to worry about "packing material" deteriorating and getting louder after as little as a few months. The interior case volume of the inside of a Flowmaster muffler is far superior to that of a "straight-pipe" or "straight-through" muffler design. Imagine filling a "straight-pipe" or "straight-through" muffler with water vs. filling a Flowmaster muffler with water. Which one do think would hold substantially more volume? The deflector in a Flowmaster muffler acts as a one way check valve eliminating reversion back to the engine and creates a low pressure area to help scavenge the exhaust. Flowmasters unique style of H-Chamber designs help control interior resonance inside the cab area of your vehicles. "Straight-through" muffler designs cannot. Flowmasters use fully welded construction for added strength and durability to last even when installed on high horsepower engines.
Flowmaster mufflers are made in the U.S.A.
- Fits 99-04 GT, 2001 Bullitt, and 03-04 Mach 1, will not fit Mustang Cobra equipped with IRS.
- 2.5" Inlet / 3" Tip
- Super 40 Series Mufflers
- Aluminized Steel Construction
- Stainless Steel Tips
Flowmaster, the exhaust technology company, has deep roots in the Mustang performance exhaust history. The Flowmaster 2 chamber muffler was one of and still is one of the most sought after exhaust additions to any Ford Mustang. Their deep throaty exhaust was made super popular during the Fox Body Mustang era with their 2 chamber 40 series mufflers that have now become muffler legends. Since then Flowmaster has evolved and branched off into more than just great sounding mufflers.
They now produce some of the best sounding and highest quality cat back and axle back systems. They also produce high flow catalytic converters, long tube headers and mid pipes to ensure they have every component you need to finish your Mustang exhaust project off the right way! Click the link above to see the full line of Flowmaster exhaust component for your Mustang.
In the early 1980s, Flow Master Mufflers were born to combat excessive sound issues at race tracks in California and all across the US. One patented innovation led to another and evolved into the company it is today. All Flow Master products are proudly manufactured right here in the USA and will improve the sound and performance of your Mustang or Lightning.
Latemodelrestoration.com carries full cat backs, axle backs, individual mufflers, and catalytic converters. If you're not viewing this video on our site, click below to check out our Flow Master offering and give your Mustang or Lightning the signature Flow Master sound.
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!
Thanks LMR. You provide great service. I'm not a mechanic but with a jack and jack stands I was able to install the flow master cat back in four in a half hrs. It really sounds great on my 01 GT convertible. Not too loud and in my opinion just right. Directions from flow master are "just OK" but can be figured out with common sense. Just a heads up, you will need a 13 and 14mm deep socket to complete the install. (Which I didn't know) I'm very happy with the whole buying experience and the end result.
Yes, I would recommend this item to a friend!
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Ordered a couple weeks ago received tracking info ASAP got eaxactly what I ordered could not be happier Not too loud can come home and you won't here me coming unless I want you too (still pleanty loud when you step on it)
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!