So after months of nagging, Flowmaster finally developed a GT500 axle back kit and sent me out a couple prototypes to test out.
Fit and finish:
409ss construction with polished 4” tips and stock-style side-slash cut tip design. The kit is a prototype due to the quad tips but the mufflers are also a prototype hybrid muffler that combines the classic chambered case (deep sound) with the straight through design of flowmasters’s Outlaw mufflers (higher flow). The mufflers fit perfect and went in easy. The tips are not double walled but they are noticeably larger than stock and the polishing is carried slightly over the edge of the tip so they do show up more than the stock tips.
Sound:
Let me clarify, I like aggressive (loud) exhaust. I prefer the deep “big-block” sound of a chambered muffler to the raspy sound of most of today’s “straight-through” mufflers. I have had a number of Mustangs/Cobras and every one eventually had an offroad h-pipe and performance mufflers. My Shelby has an offroad so keep that in mind. So, I’m not new to some noise. That being said, this system is DEEP and LOUD when combined with my offroad. Flowmaster accomplished that deep chambered sound for sure. The sound alone sells me. The loudness is another matter.
Why so loud? Flowmaster designed this system for Shelby’s with the stock/catted h-pipe. They openly said they knew how aggressive the stock mufflers were and did not want to make a quieter muffler. In my opinion, I think on a stock catted h-pipe, this system would be mean and perfect. I would recommend it for the guy not wanting (or unable) to eliminate his cats yet wants a deep aggressive sound. Now, If you have an offroad and like some serious volume and a unique (deep) sound that is different from the other Shelby systems out there, then I’d recommend it for you too.
Drone: First, I will say that I cringe when guys with muscle cars ask over n over, “does it drone?” I mean, I get it, but I also feel a muscle car should sound deep and drone just comes with a deep sound. That being said, with an offroad, these things do drone quite a bit! This isn't for those who dont like some interioir volume for sure. Seriously! Again, I feel it’s due to them being designed for a stock catted system but they would likely still drone a little even with cats. Loud and deep equals drone.It’s all about the deep sound though. The car sounds deep and mean so it’s hard not to fall in love with the sound. I’m serious when I say (and some cobra owning friends agree) this exhaust has BASS! You feel it when you stand behind it. I thought the Magnaflow race (no muffler) design would be the loudest possible setup but these take the sound, deepen it and then almost magnify it.
Videos should be listened to with earbud style headphones to get the true feel of the deep tone and bass.
FYI… I’ll have one of these systems for sale in the near future.
Oh and if all you have to say is negative, then save it. I posted this so others can see the options out there. The system is still undergoing changes. Thanks to Flowmaster for using me as a lab rat
[/URL][/IMG]
Stock (left) vs. Flowmaster (right):
[/URL][/IMG]
[/URL][/IMG]
[/URL][/IMG]
"]
VIDEO (click image):
[/URL]
VIDEO (click image):
[/URL][/IMG]
VIDEO (click image):
Fit and finish:
409ss construction with polished 4” tips and stock-style side-slash cut tip design. The kit is a prototype due to the quad tips but the mufflers are also a prototype hybrid muffler that combines the classic chambered case (deep sound) with the straight through design of flowmasters’s Outlaw mufflers (higher flow). The mufflers fit perfect and went in easy. The tips are not double walled but they are noticeably larger than stock and the polishing is carried slightly over the edge of the tip so they do show up more than the stock tips.
Sound:
Let me clarify, I like aggressive (loud) exhaust. I prefer the deep “big-block” sound of a chambered muffler to the raspy sound of most of today’s “straight-through” mufflers. I have had a number of Mustangs/Cobras and every one eventually had an offroad h-pipe and performance mufflers. My Shelby has an offroad so keep that in mind. So, I’m not new to some noise. That being said, this system is DEEP and LOUD when combined with my offroad. Flowmaster accomplished that deep chambered sound for sure. The sound alone sells me. The loudness is another matter.
Why so loud? Flowmaster designed this system for Shelby’s with the stock/catted h-pipe. They openly said they knew how aggressive the stock mufflers were and did not want to make a quieter muffler. In my opinion, I think on a stock catted h-pipe, this system would be mean and perfect. I would recommend it for the guy not wanting (or unable) to eliminate his cats yet wants a deep aggressive sound. Now, If you have an offroad and like some serious volume and a unique (deep) sound that is different from the other Shelby systems out there, then I’d recommend it for you too.
Drone: First, I will say that I cringe when guys with muscle cars ask over n over, “does it drone?” I mean, I get it, but I also feel a muscle car should sound deep and drone just comes with a deep sound. That being said, with an offroad, these things do drone quite a bit! This isn't for those who dont like some interioir volume for sure. Seriously! Again, I feel it’s due to them being designed for a stock catted system but they would likely still drone a little even with cats. Loud and deep equals drone.It’s all about the deep sound though. The car sounds deep and mean so it’s hard not to fall in love with the sound. I’m serious when I say (and some cobra owning friends agree) this exhaust has BASS! You feel it when you stand behind it. I thought the Magnaflow race (no muffler) design would be the loudest possible setup but these take the sound, deepen it and then almost magnify it.
Videos should be listened to with earbud style headphones to get the true feel of the deep tone and bass.
FYI… I’ll have one of these systems for sale in the near future.
Oh and if all you have to say is negative, then save it. I posted this so others can see the options out there. The system is still undergoing changes. Thanks to Flowmaster for using me as a lab rat
Stock (left) vs. Flowmaster (right):
VIDEO (click image):
VIDEO (click image):
VIDEO (click image):
Last edited:
