Talk to a Mustang Expert
1-888-332-7930
M-F 9-9,Sat 9-5:30,Sun 12-4 ET

Free Shipping on Everything. Seriously. Details

Flowmaster American Thunder Catback Exhaust w/ X-Pipe (13-14 GT)

17 Reviews
Our Price

$786.84

  • Item #18446
  • MPN# 817587

  • Market Price $873.99
  • You Save 10% ($87.15)
In Stock Ships same business day.
Free Shipping on Everything
REBATE AVAILABLE Details
Product Videos Customer Photos
Features
  • Aggressive Flowmaster 60-series Delta Flow sound
  • Durable 409 stainless steel construction
  • 3" mandrel bent tubing
  • 4" polished stainless steel tips
  • Includes Scavenger X-pipe and two Flowmaster 60 series mufflers
  • Fits 2013-2014 GT
Description
Signature Flowmaster Sound. Give your Coyote Mustang that unmistakeable Flowmaster sound with the American Thunder Catback Exhaust system from AmericanMuscle. The Flowmaster American Thunder Catback 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.

Race Car Growl. The included Scavenger X-Pipe not only helps increase power, but it also adds a loud raspy, race car growl to the sound of your exhaust with its modern "X" crossover pipe design.

Quality Construction. Constructed from durable 3" 16 gauge 409 stainless steel tubing for it's corrosion resistant properties the Flowmaster American Thunder Catback 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 Catback exhaust system is designed to fit the 2013-2014 5.0L Coyote Powered GT Mustang for both great looks and great sound. Does not fit Shelby GT500 models.

Fitment: 2013 2014 Details

Won't fit? Add an exception

What's in the Box
  • (1) Right muffler assembly
  • (1) Left muffler assembly
  • (1) Scavenger X pipe assembly
  • (1) Right intermediate pipe
  • (1) Left intermediate pipe
  • (4) Band clamps
  • (2) Hanger keepers
Installation Info
Tech Specs
Axleback Exhaust Specifications
Piping Material: 409 Stainless Steel Tip Material : Polished Stainless Steel
Piping Size: 3.0" Tip Size: 4.0"
Muffler Type: Chambered Fitment: 2013-2014 GT
Will it fit my Mustang?
  • Boss 302 - 13
  • GT - 13, 14

Most Helpful Reviews

5/5
Loud, but not too loud.

Mustang GTs have always turned my head for the way they sound. I thought after buying a 2013 that the last thing I'd do was put an exhaust system on it. Well, that was the second thing I did to it after ...

Read More
Helpful (2)

5/5
Great sounding exhaust!! It's what a mustang should sound like! !

I was ify about buying this item because of the bag fitment reviews it received. I thought to myself for the price I'll deal with it. Turns out it went right in with no issues what do ever. I can only ...

Read More
Helpful (2)

Read All 17 Reviews
Overall Rating 4.7 out of 5 stars

Videos

Hey I’m Justin with AmericanMuscle.com, and I’m breaking down Flowmaster’s American Thunder Catback exhaust, fitting the 2013 Mustang GT. Flowmaster offers a number of mufflers all with their own unique View Full Transcript

Customer Photos (3) View All Photos

You Might Also Like

3 Questions / 4 Answers

Ask a Question

does this only fit on stock or can i get short tube headers and this to bolt on after? i want to get shorty ceramic headers, and an exhaust system all the way back for better flow. will that work?

Mike12 Year: 2013 Model: GT

  • Absolutely! Ceramic Shorty Headers would be a great complement to the American Thunder Catback. Hope this helps!

    LisaS Year: 1992 Model: GT

    Good Answer (0)

Show 1 more answer Question Resolved

Would this exhaust go well with some long tube headers without a problem such as the bbk or pypes longtubes?

Richeh Year: 2013 Model: GT

  • As long as the long tube headers had the ball socket connection on the end. If not you would probably have to get an exhaust shop to install them

    fast5ohh Year: 2013 Model: GT

    Good Answer (0)

Question Resolved

Cause check engine light? Will this system cause the "Check engine" light to come on?

uttersqueez Year: 2011 Model: GT

  • No it will not cause a check engine light. It does not remove the catylitic converters

    fast5ohh Year: 2013 Model: GT

    Good Answer (2)

Question Resolved

More Products You Might Like

Customer Reviews (17) Write a Review

Overall Rating 4.7

out of 5 stars

Installation Time:Full Day

Installation Cost:$100-$250

  • Loudness / Volume 4.588235 4.6
  • Exhaust Note 4.823529 4.8
  • Fit & Finish 4.352941 4.4
  • Bang For Your Buck 4.529412 4.5



  • 5/5

    Installation Time: Less than 1 Hour

    May 06, 2014

    Great sounding exhaust!! It's what a mustang should sound like! !

    I was ify about buying this item because of the bag fitment reviews it received. I thought to myself for the price I'll deal with it. Turns out it went right in with no issues what do ever. I can only imaging those customers did not wait to the end to tighten everything. Great item. I love the exhaust note it has! It's what a 5.0 should sound like! Performance wise I didn't notice any gains but a catback is mainly for sound and not power. I'm all stock except for the catback.

    SlowGrabberBlue

    Year: 2014 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 5+ Phoenix, AZ, USA

    Helpful (2) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    March 22, 2013

    Loud, but not too loud.

    Mustang GTs have always turned my head for the way they sound. I thought after buying a 2013 that the last thing I'd do was put an exhaust system on it. Well, that was the second thing I did to it after a C.A.I. and am I glad I did. Not only does it sound better, but I can notice the difference in acceleration. I'm quite glad I didn't get the Outlaw, for it might be too loud. My neighbor said he wasn't hearing me start my Mustang (he has a SS Camero) and was wondering if I drove it at all. He hasn't asked that after the Flowmaster American Thunder was installed.

    Roysun

    Year: 2013 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Salisbury, NC, USA

    Helpful (2) (0)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    May 19, 2014

    WOW!!!

    I have always used Flowmaster products on all my vehicles-from Corvettes to pickups!! They have always sounded good and improved performance! But, on my 13 GT it has outdone itself to the max!! It has a low rumble at idle,a great roar on full throttle accel and a nice tone at cruising speeds up to 80 mph!! Best investment I have ever made!! And at steadt hiway speeds has increased my gas mileage to boot!! LOL good deal all the way around!!!

    horsearound

    Year: 2013 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Raeford, NC 28376, USA

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    July 01, 2013

    Best 5.0 exhaust!

    When I first installed this system on my car there was a major fitment issue. I called AM and they sent me a brand new kit! After installing the second system it was perfect. The sound alone makes this exhaust worth the problems. The stainless steel is average quality but none of that matters when you hear the sound it makes! Its not a quiet exhaust but its very pleasant and mellow at low RPM. I would recommend this exhaust over any other system. I'm not sure about power gains as I installed this with a CAI and tune.

    GTEd2013

    Year: 2013 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 2

    Helpful (1) (0)

  • 5/5

    Installation Time: Less than 1 Hour

    May 14, 2013

    Love the sound

    Sounds a lot louder than my friends magnaflow cat back . But his goes from the h pipe. Glad I didn't waste my money on that exhaust . Also like the little extra power.

    goodfun

    Year: 2013 Model: GT Driving Style: Street / Strip 'Stangs I have owned: 1 nj

    Helpful (1) (0)

  • 3/5

    Installation Time: Afternoon

    May 08, 2013

    Not all that impressed but not to bad.

    The scavenger pipe was well made with excellent welds. The fit was off connecting to the existing cats but it was mentioned in the manual and was easily adjusted. Measure and dry fit prior to installation. It was noticed that if you are not installing this system on a lift the old over axle mid pipes will not come out without at least 24” of ground clearance. Be aware and use a saw or angle grinder to cut them as close to the rear axle as possible. The fit is tight and exact but the hangers on the mufflers are not welded very well and had to be removed and re-welded in order for proper fit. Some quality issues on mufflers with paint. In order to get the mufflers mounted in the hangers, the forward hanger on the drivers side had to be removed then reinstalled with the muffler in it and the passenger side mid pipe had to be moved forward. Minor issues in all.

    Duke5

    Year: 2013 Model: Other Driving Style: Daily Driver 'Stangs I have owned: 2 Texas

    Helpful (1) (0)

  • 5/5

    Installation Time: Afternoon

    September 18, 2013

    Great sound with the stock headers and cats!

    Excellent product and this is the first exhaust system that I have purchased for the new 5.0s. I have bought Flowmaster in the past and I was satisfied with the sound and installation.

    Paul74

    Year: 2014 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 5 Cape Coral, FL, USA

    Helpful (0) (1)

  • 5/5

    Installation Time: Afternoon

    July 24, 2013

    Sound Awesome!

    The exhaust sounds very nice cruising around and is not overly loud. The fitment was slight off. After installing the exhaust myself and spending hours trying to get it to line up I gave up and took it to an exhaust shop. They took it off and the left side (drive side) pipe was about an 1" off on the bend. They re-bent it and installed it. Now its perfect. Love the sound, but after paying a shop to fix the bend I could have gotten the Borla's. I do recommed this product and imagine it was a 1 in million product defect. I have numerous other Flowmasters and they have been perfect.

    lwevert

    Year: 2014 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 2 Honolulu, HI

    Helpful (0) (1)

  • 5/5

    Installation Time: Shop Install

    Installation Cost: $100-$250

    July 20, 2015

    The boy sounds like he"s become a man

    This exhaust is a grade above the stock equipment. Love the roar it creates especially on cold starts and I can't help punching it. Gives me what I felt a Mudtang should sound like.

    Bushmaster

    Year: 2013 Driving Style: Daily Driver Port Reading, NJ

    Helpful (0) (0)

  • 4/5

    Installation Time: Afternoon

    June 07, 2015

    American Thunder Cat Back

    American Muscle shipped fast and arrived in good condition even though the box had little packing material in it. I did this install on a few days ago, started at 430 and didn't finish till 10 pm, taking off the factory exhaust is not easy but that was just the beginning. We put the car high in the air with 4 jack stands and we still had clearance issues getting the flowmaster mid pipes over the axles. I don't recommend trying to install this exhaust unless you have a lift for clearance reasons. Due to the fact that we couldn't get mid pipes over the axle we had to drop the whole rear end to have enough room to complete the exhaust. Once on ,everything fit really well with no more issues. This was a difficult install but it was worth it, the tone of this system is fantastic, slightly louder then stock at idle but even a touch of the gas pedal let's loose this great deep tone flowmaster is known for. As well there is no irritating drone at high way speeds. I recommend this system 100

    Matt

    Year: 2013 Model: GT Driving Style: Daily Driver 'Stangs I have owned: 1 Tampa FL

    Helpful (0) (0)

Related Categories