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SKU #: DE800464-main Diamond Eye Performance 51" Big Dog Quiet Tone Muffler

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So you're like many and are tired of the noise, or maybe its just your neighbors complaints you're tired of. Either way, the Diamond Eye Big Dog 51" muffler may not be for everyone, but its a great s ... read more

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So you're like many and are tired of the noise, or maybe its just your neighbors complaints you're tired of. Either way, the Diamond Eye Big Dog 51" muffler may not be for everyone, but its a great solution for many. Many people have realized the very noticeable increase in sound level and drone when going from a 4" to a 5" exhaust system. Many people like the extra decibel, but some simply dread it, but require the 5" in order to keep EGT's at a tolerable level. If you're the latter, then you need a Big Dog Quiet Tone muffler.

This enormous 51" muffler has the ability to drastically cut down on the interior and exterior sound to create a nearly "sleeper" truck. The only thing we caution those interested in this muffler.....MAKE SURE YOU'VE GOT ROOM FOR IT! Many extended cab short box, as well as other vehicles, simply don't have room for a muffler this long. But if you've got the room and are tired of the noise, install this muffler. It still performs every bit as good as all of Diamond Eye's other smaller mufflers, but with greater sound control.

This muffler is directional, the domed side of the body is the outlet, the lipped side of the muffler is the inlet.


  • ManufacturerDiamond Eye Performance
  • MPN800464 | 800465


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7 Reviews

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Rate Diamond Eye Performance 51" Big Dog Quiet Tone Muffler

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Verified Buyer
Definitely cuts down the noise
Definitely cut down the noise on my 5” exhaust. At idle, it has a nice deep throaty tone, louder than stock for sure, but not that much. While driving, it seemed to be extremely quiet like a stock. It was too quiet in my opinion though, it’s easier for me to tell what my engine is doing with the straight pipe. But again, that’s my opinion. But this muffler did exactly as described and definitely cut down on noise.
Store Reply
Right on! Hard to judge what exhaust is really going to sound like until you hear it in person. Glad you like it! Those mufflers work great. Have fun with your newfound power and sound. Stay safe.
Verified Buyer
Stealth mode Activated!!
Driving a 08 Cummins MegaCab with 6.7 with over 600 hp and straight pipe exhaust for years has taken its toll on my hearing, time to go stealth mode!! This muffler was better than expected, its honestly not much louder than stock!! Get on the loud peddle an its still very quiet, gotta say its kinda weird stomping the skinny pedal an WHOOSH stealthy like a true sleeper. Some guys installed resonators with this muffler, no idea why this thing is huge but man is it quiet!!! If you got the room an want to hear the motor not the exhaust then this is the one to get!!!! Fast delivery!!!!
Store Reply
Right on Lance! Thank you for the useful information and your review. This muffler is a fan favorite for the exact reasons you stated. Nothing like whooping up on an import, while still being able to listen to talk radio. -Ben
Best muffler ever, great customer service
Definately five stars
Store Reply
Thanks for your order and your review John. -Ben
Verified Buyer
muffler came very poorly packed with several dents , its a thin gauge some sort of stainless steel ok got over that , put it on my cummins powered pete, adverse to the write up it did NOT ! quiet down my truck in fact its louder than oem muffler,are very mis leading, or are they flat out liars???,
Great muffler if you want to lower your exhau...
Great muffler if you want to lower your exhaust noise, but remember it is 51 long.
I replaced my 4 Flowmster muffler with this m...
I replaced my 4 Flowmster muffler with this muffler. It made my 1999 F250 7.3 as quiet or quieter than stock. It really really improved the drone noise in the cab when pulling trailer.
Good muffler at a good price.
I built my own 5'' turbo back exhaust on my 2004.5 dodge ram 3500 4 door long box (almost 22' long) and needed a muffler because the in cab noise level was 98 decibels while towing heavy loads over passes. This muffler did the trick by lowering the in cab noise level by at least 75% without performance loss and still have great sound from the tail pipe .The only thing I would recommend is that you make sure this muffler will fit under your truck before you order it. It's 51'' long and 10.5'' diameter. It barely fits between my carrier bearing and frame. And make sure you are ready to make custom hangers too.

will this muffler work w/ DE-K4235A-2 or will i still need a section of pipe requiring me to purchase the DE-K4235A instead? 06 mega cab?

You could run it with the -2. Just triple check that you have enough room. Those mufflers are huge.


I have a 2013 Ram 2500 Cummins with a 5"" exhaust. Will this fit in the space under my truck between the drive shaft and frame? Also, what is the return policy if it doesn't fit for some reason??

I would measure at least three times to see if it will fit. If you have a short 6'6' bed more then likely it wont fit. If you have a long bed it may. Check out or returns link at the bottom of our page for return info.


What's end of the muffler is the inlet or what end is the outlet? I noticed one end is indented in and the other is domed out. Thanks.?

The side that is recessed in is the inlet, the domed out is the outlet.


Does it fit on a mega cab short box??

Most of the time there are no fitment issues. We would still suggest measuring under your truck to verify you have the correct space.-TL


Is this a full flow or straight through type? I'm looking for one that's not straight through. I want almost no tailpipe noise on a class 8 truck. Thank you in advance?

This is your best shot at killing as much noise as possible without sacrificing power or flow. This is not a chambered muffler, but it is also not a straight through... best way to describe it is, baffled. -Ben


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Diamond Eye Performance 51

Diamond Eye Performance 51" Big Dog Quiet Tone Muffler

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