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Flowmaster 817669 American Thunder 409S Cat-Back System with Aggressive Sound

  • Based on 73 reviews
Condition: New
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Availability: Only 6 left in stock, order soon!
Fulfilled by Amazon

Arrives Friday, May 24
Order within 17 hours and 29 minutes
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Features

  • Stainless Steel Construction
  • Great Performance Tone
  • Patented Delta Flow technology
  • Lifetime Limited Warranty

Description

Flow master 817669 American Thunder 409S Cat-Back System with Aggressive Sound


Manufacturer: ‎Flowmaster


Brand: ‎Flowmaster


Model: ‎817669


Item Weight: ‎62.5 pounds


Country of Origin: ‎USA


Item model number: ‎817669


Is Discontinued By Manufacturer: ‎No


Exterior: ‎Painted


Manufacturer Part Number: ‎817669


OEM Part Number: ‎817669


Date First Available: October 24, 2013


Frequently asked questions

If you place your order now, the estimated arrival date for this product is: Friday, May 24

Yes, absolutely! You may return this product for a full refund within 30 days of receiving it.

To initiate a return, please visit our Returns Center.

View our full returns policy here.

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Top Amazon Reviews


  • READ FIRST BEFORE YOU BUY!
Style: Base Product
Ok, READ BEFORE YOU BUY. Let me say that overall I am happy, yes. I'm going to elaborate on a few other reviews that I've read on here and share my experience simultaneously. 1. "Clamps didn't tighten enough to hold it together" - Align the clamps with the very edge of the pipe that overlaps the smaller diameter pipe. There are cutouts that look like misaligned rectangles on the ends of these pipes that are designed specifically for this purpose. As you tighten the clamp, the metal will constrict the smaller pipe with the assistance of the cutouts (you will see it happening before your very eyes). They cramp down for you, giving you the tighter hold that is needed to hold your pipes together. No need to go out and buy other clamps. I only know this because I ran into the same problem, but we were able to get past it with this tip. Be ready to go at it with full force, the clamp nuts come out of the box pretty tight already. 2. "Welded holders not in right spots" - One of two things happened here, either you didn't buy the right size system for your truck or you didn't use the extension pipe they gave you in the box. Neither is bad, both are quick fixes. I would highly recommend you search your vehicle using resources such as your VIN number online to find the necessary specs (specifically, engine and bed size). Don't just guess! You'll have peace of mind knowing you have the knowledge to back up your order, and you'll pat yourself on the back later. - The second thing would be the extension pipe. My bed is the 5-footer (give or take a few inches), but my order came with an extension in the event that my bed was the 6-footer. Again, this goes back to knowing the dirty deets for your truck, but that could very well be a reason for your misplaced holdings. 3. "Cutting the stock exhaust to make it easier to remove" - I chose not to do this simply for the luxury of having the choice to revert back to it later on, should I so decide. I also did not use a hoist to suspend my truck, I only lifted it to where the tires were a few inches off the deck and put the rear end of my truck on two towers (I delivered the ring to Mt. Doom the next day) ((<--sorry if you didn't get that reference)). Yes, it was a bit difficult to pull it out, but it's not impossible. I spent, at most, five (5) solid minutes pushing and pulling the thing until it wormed out. Come on, though we're all truck drivers here, we have the patience and skill to take an 8-point turn if deemed necessary. On that note, generously spray the rubber holdings with WD-40, leverage will do the rest. Those puppies will pop right out. With all of this, completion time still hovered around 2 - 2.5 hours. Did I mention it took two of us? 4. "You'll need an impact" - Not necessarily. Sure, it's the absolute safest bet, but a cheater bar will do you just fine. If you don't know what that is, it's a shorter way of saying "add-more-torque-to-your-tool-by-extending-the-ratchet's-handle-using-a-hollow, steel-pipe". This will make it easier to turn the ratchet using less force on your end (sorry, physics lessons only every other Tuesday). Course, do as you will. So why 4-stars? I was under the impression that my order would come with chrome tips (as is pictured), but instead I got a sort of matte-black finish tips. It's not a terrible alternative, I was just side-swiped by the lack of parallelism between what was advertised and what was delivered. It shakes my garage at star-up, it's awesome. Some Honorable Mentions: - You have to install another rubber holding on the left side of the truck (don't worry it comes in the box). I was stumped looking for the spot to place it on the right side of the frame like an idiot before I realized that this was a dual-pipe system, so of course I would need a holder on the left side. The best way to find this spot is to kneel just behind your rear, driver-side tire and look right at your spare. You should see the frame there, it's got a round hole that you could see through almost to the other side, and to the right of that is a smaller hole. That's what she said. Also, that's the hole you want. That's also what she said. - Order goes bolt, locking washer, washer, internal star, frame, steel square piece, internal star, nut. - Be sure to level the piece that you attach your tail pipes to SIDEWAYS. I initially put them on where the "S-ed" downwards instead of sideways. Best of luck! Feel free to comment or question. ... show more
Reviewed in the United States 🇺🇸 on June 10, 2016 by Elson

  • Sounds Great, Easy to Install.
Style: Base Product
I purchased this exhaust for my 2014 Silverado LTZ Z71 Crew Cab 5.3L gas truck. Start to finish it took 2.5 hours to remove the OEM exhaust and install the new Flowmaster. I installed it with a 3/8” drive ratchet, 10, 13 and 15 mm deep well sockets. A hack saw was used to cut behind the original muffler for removal of the Tail pipe section. No pneumatic or electric tools were used. I did need to use a cheater bar to supply sufficient torque to tighten the clamps. The sound is great. Start-up of the vehicle delivers a good rumble to let you know the exhaust is there! When the engine is idle the exhaust is very tame. Putting the truck in gear and hitting the gas delivers that great Flowmaster sound one would expect from there proven exhausts. The low RPM sound is amazing, delivering a very deep rumble that will turn heads. As you accelerate through the RPMs the sound of the exhaust gets more of a higher pitch sound but still rumbles with great presence. The deep rumble returns with the shifting of each gear in the automatic transmission. While cruising at any speed that the computer deems necessary to switch to V4 Mode, the exhaust exhibits a drone that is not annoying after the second time you hear it. The drone usually doesn’t last long as the truck with any form of road incline automatically switches to V8 Mode and returns to the great Flowmaster sound. There was no additional cutting or welding needed. Though the clamps are probably sufficient enough to last a life time (heavy duty), spending the extra money to have the exhaust welded up would probably be the safest bet. I plan to have it welded up soon. ... show more
Reviewed in the United States 🇺🇸 on November 24, 2014 by Brandon C. Darke

  • Whole system rusted after a year!
Style: Base Product
This 817669 exhaust kit leaves a lot to be desired as far as the clamps and left pipe assembly. Everything else is excellent. The clamps are garbage. Don't waste your time with them. I spent over 4 hours installing and reworking the system on my 2016 Silverado crew cab short bed 5.3. I used ramps and jack stands to hold the truck higher at ride height and to hold the piping and muffler. Having the truck at ride height was important as the clearance of the left pipe over the axle has only a few inches of clearance. (I lowered my truck 3" in the rear) and the axle hit the left pipe just a little over a big bump with 5 people inside. So stock ride height trucks should have plenty of room. The left pipe is an assembly of three pipes plus the tip, and the right pipe is only two plus the tip. The left pipe gave me a lot of trouble and it still doesn't match the angles of the right pipe/tip... I bought Dynomax/Walker mega band clamps to replace all the clamps. I strongly recommend ordering 5: 2 1/2" & 1: 3" lap joint stainless steel band clamps! Have them on hand when you go to install this system. I'm using Dynomax part numbers 33226 & 33272. About $65 extra expense to add to this system. Also I drilled a 1/8" weep hole in the bottom rear of the muffler case. It drains water to avoid the "rustmaster." The little bolts on the tips need to be tightened with a 1/4" ratchet by hand. I got them to stay put. The super 40 muffler gives that classic flowmaster sound during acceleration and is a perfect low rumble at idle. In V4 mode it sounds weird due to the stock exhaust having a flapper valve to compensate for this. So without the valve V4 mode is different but not annoying at low speeds with light to part throttle. I'm sure I'll get use to it. From what I've heard since installing overall sounds good especially compared to the stock system! But at 70-80mph you really hear the muffler. I would have preffered it to be quiet at high speed. But I guess I shouldn't get sleepy on a long road trip. Update after a year: the whole system is rusting, the muffler and hangars especially, even the pipes show surface rust. Very disappointing. But I should have known better. Flowmaster has been known to be called rustmaster. Now I see exactly why. Glad I drilled that weep hole, a ton of water has drained from there. We bought a Borla system for our other Silverado and it came with a weep hole already, so does the factory muffler. That's quality. Needless to say the borla system shows no signs of rust 4 months later and I don't expect to see any rust either from that borla. And it's overall just a way better system, yes you DO definitely get what you pay for. Don't be cheap if you care about your truck looking it's best outside and inside and underneath too, buy the Borla system. I lowered to 2 stars because it's still functional, and for the most part sounds good, but annoying in V4 mode and cruising on the freeway at 75-80 which is where everyone cruises, so we either have to go slower or faster than the speed of traffic. Anyway, don't waste your time or money on flowmaster... ... show more
Reviewed in the United States 🇺🇸 on June 7, 2017 by Eddie&Alexandra Rivera

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