Hey Guys, so for a long time I have been wanting to change my muffler on my truck. 2004 F150 5.4 (Stock) I wanted something that had a nice rumble but not too much cab noise. I have been stuck on the Flowmaster 50 Delta Flow or the Flowmaster 40 Delta Flow.. I was worried that the 40 would be too loud. I got the 40 installed today. All I did was change the muffler and add a pipe because the Flowmaster was smaller. I am very happy that I got the 40!! I honestly thought it was going to be A LOT LOUDER!! I know it is going to break-in and will be a little louder. I know you can remove the resonator if you want it louder. Overall I think this muffler has a beautiful sound when you open it up and almost no cab noise. At idle is has a nice rumble. On the highway @ 110km/h I would say it is about 10-15% louder if that. I just wanted to post this for anybody who wants a Flowmaster 40 and is worried about the cab being too loud. Hope this helped somebody!

 

Hey Bones, I did the same thing. Bought a 50, went back just a few days later and got the 40. Very happy with the 40.

 

I like the louder of the two myself. I like the FM 2,000rpm cabin drone

 

x2, i could listen to it all day

 

You guys like the cabin drone?

I hate chambered mufflers. I will only use straight through or turbo mufflers. I would rather have a glasspack than Flowmaster. I prefer Magnaflow and Dynomax.

Nearly any straight through muffler will flow better.