You won't be so happy in a couple of years when it falls apart. I learned the hard way. Nice sound, poor flow and longevity.

I went with just the SI/SO 3" Magnaflow on my 5.4l. It's a step up but not annoying. No in cab resonance. It has a nice cruise tone at 1500-2200 under load. Wanted to keep the system all Stainless.
Was originally looking at the Flowmaster 50 series SUV.

I have original 40's Flowmasters on my big chevy. It has 12" lift kit so the interior resonance isn't that bad and it dumps before the rear axle. Has a 2.5" custom built with an X-pipe. Sounds pretty gnarly!! I love that Flowmaster sound. I guess it is what ever you prefer. :-X06

I noticed the same thing, its got an awesome tone at low rpm under load, but once you get into the pedal it quiets down, and this system originally came off my 2.8 v6 s10 and remarkably on that truck this system was obnoxiously loud.... Also the s10 has been sitting for about 5 years outside and its lowered so the muffler couldnt have been more than 4 inches off the ground and i have no rust problems, so i think its safe to say flowmaster mufflers are quality! Have a listen- YouTube - F-250 Superduty Flowmaster Exhaust
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It's funny, but a lot of guys completely forget about Dynomax mufflers despite them giving the low tonal quality and sound that a lot of people like.

I've never been a fan of Flowmaster's sound(s).

I have an '08 F250 4X4 with the 5.4L. The time has come to replace the muffler as there is now a small hole (approx the size of a dime) and a 1 1'2" crack along the side seam at the back of the muffler. I would like to go with either a Flowmaster or Magnaflow but the DW doesn't want it loud in the cab. Especially when giving it gas towing our TT up a hill. The closer to stock sound the better for her. A deep mellow sound is ideal for me. Has anyone replaced their muffler with something that isn't going to be defining in the truck? Any advice is appreciated.

I have an 08, 250. 4x4, with the 5.4. I have the flowmaster 40 and wish I had done the magnaflow. Resonates in the cab, especially pulling my TT.

I have dual Magnaflows on the wife's 2007 Lincoln LT 5.4 and a single on my 2008 V-10. Love them both.

The issue that you are experiencing with your exhaust system is not due to the fact that you have a Flowmaster muffler, but rather that you have the incorrect series of Flowmaster muffler installed for your application. The 40 Series muffler that you have is quite aggressive and not especially tow-friendly. Here is a link to the recommended mufflers and kits that we offer for your truck. Our 50 Series HD mufflers are better suited to the needs of tow vehicles. Best of luck to you!

Great info Matt. Thanks! I had a local shop do the work cause they did a good job on my other truck. Not so much with this one. I think the shop has new owners and this guy just wants to make a buck.

No problem. I always recommend that people call in and speak with one of our customer service representatives, prior to purchase, to find out which part number will best fit their needs and budget. Good luck!