Flowmaster 40 series question

[Sinraptor]

Hi guys, I'm decided I want to install a Flowmaster 40 series muffler on my 5.4 scab. I just need some questions answered? Like I'm guessing I would need the 3.00 Offset In / 2.50 Dual Out muffler style correct? And would the muffler shop have to do any modifications to the piping for clearance, extending pipes out or adding extra piping if the Flowmaster Is shorter than stock muffler? Has anyone done this and what had to be done to make it look stock with new muffler? My muffler guy is really good but I like o know what I'm getting into and maybe help him out with some knowledge before we go into it blind. Thanks guys any info would really help me out!

 

[BIRDMAN]

All they need to do is cut and slightly flare the factory "3 inch" pipe coming off the flange and weld in a short length of 3" pipe to connect to the Flowmaster. The reason for the flaring is the pipe coming from the cat-back flange isn't quite 3". Then if they cut the factory tailpipes off the muffler they should be able to hook right in to the Flowmaster and maintain your stock look. They might need to weld in an additional hanger or two but it should be easy and yes you need the 3" in dual 2.5" out.

 

[whtrapta]

I have the 40 series. In not too crazy about it. It's a 3 in/3 out. Normal driving its nice. Quiet in the cab but has a nice growl outside the truck. The thing I don't like is under hard acceleration there is a very Lou whooshing sound that overpowers the growl. Not a nice sound.

 

[Sinraptor]

Thanks alot guys that really helps. Also anyone have experience with Shorty Headers on a 5.4L? How hard are they to install? Will i have to take loose motor mounts, alt., or wheel or wheel house liner to get to anything or is it direct fit and has enough clearance to take out manifolds and install headers right back? Thanks

 

[Jay]

I have the 40 series on my 6.2 it sounds all right to me. I wanted the SW lightning but i couldn't see spending that much. I opted for the cheap route $80 for the muffler and $50 for someone to weld it in.