I took off my muffer and put a dual in dual out 2.5 inch super 40 flowmaster on it about 5 months ago and it sounds sweet outside the cab. I am finally starting to get tired of the interior resonance of the flowmaster. Does anyone have any experience with this motor/exhaust setup and can recommend either different muffler that will still sound good outside but wont be so loud inside. thanks Brad

Thats just one of the drawbacks, if you can call it that, of a 40 series Flowmaster. If you want to turn down the interior resonance, might consider switching to a 50 series or higher. Call Flowmaster, they will probably be more than happy to recommend a quieter muffler that still keeps the same performance gains.

Try a 50 series. I have a 70 serries on my truck and is not load at all. Little loader than stock. But check out http://www.performancetrucks.net/forums/
They have sound clips with all kinds of mufflers and you can search hundreds of post on exhaust.

Thanks guys I really appreciate it.

look at dynomax super turbo. they have a good sound at higher rpm but are the quietest high flow exhaust I know of. Also Magnaflow makes a muffler that has dual one one side single on the other. It is about 24" long and 7 or 8 inches diameter, and that works well also.

I second the Magnaflow, wish I would have gone with it than the flowmaster. But I am to cheap to swap now!

ok ill have to look at their website

i have 50 on my 05 6.0L and it sounds good not to loud inside and mine just turns down 6'' after the muffler.

I guess that is an option. I wonder if that would be louder towing that having it turn outside the back tires.