I recall somewhere in a post recently about a Flowmaster replacement muffler. I'm interested in finding out more about these. I was originally considering a Gibson Side Swept Cat Back system, but if I can get a performance gain and better sounding exhaust note from a good quality freeflow performance muffler replacement at a lower cost, I'm very interested! Has anyone out there performed this mod? How difficult is it compared to a cat-back system? Can anyone recommend a good source? Thanks for the info!

Paul... :-)

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Paul... :-)
99 F-150 XLT SC Sport, 4.6L, Auto, CC
White, 4X2, Tow Package, CD, K&N Filter
More to come

 

Paul, the flowmaster 70 series(part 52571 I think) will bolt right in. I did it at home in my driveway but I don't suggest doing it yourself unless you have a cutting torch or sawzall, you have to cut off the old muffler right at the welds or you end up using an extension pipe. Either way you will have to make a new rear hanger.

The 70 series is too quite for most folks, just a little louder than stock, you really don't notice it unless you stand on it or you are towing. I did notice a slight improvement in performance. The muffler is big, heavy and exspensive, about $100., but it will probably outlast the rest of the system. The stock system on your truck is 2.5 in. and is big enough for the 4.6. I like flowmaster but there are a lot of other mufflers out there that are cheaper that will also bolt in to your present system.
Go to the exhaust system thread and start reading or you can do a search for particular brands. Lot of info there.

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98 Nascar Edition, Superchip, Airaid, Flowmaster 70 series, bedliner, in bed tool box, Profile bug deflector and window vents, Class III receiver hitch.

 

I just replaced my stock muffler with a 50 Series Flowmaster. I was told by the muffler guy that there was hardly any difference between the sound of the 50 and the 70 when doing a stock replacement. Price was $81 for muffler and $25 labor/parts. The 50 is shorter and required a short extension. As for the sound, it is definatly louder than stock when accelerating. Idling I can't tell it from stock. It has a deeper more powerful sound when accelerating (not too loud). I'm very happy with the sound (I didn't want anything to turn heads). The only thing I don't like is a slight droning between 65 and 70 MPH. All other speeds don't sound much louder than the stock muffler. I mainly changed for a performance and milage boost.


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2000 F150 Lariat Flareside 4X2 S/C, Black/Gold
5.4, 3.55 LS, Class III, Captain Chairs, CD Changer, Sliding Rear Window
Mods: PendaLiner SR Pro, Factory Body Molding, FlowMaster

 

Jonny/damorris,

Thanks for the info! I'll check around and see what's available. damorris, did you see in increase in MPG with the 50 series Flowmaster?



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Paul... :-)
99 F-150 XLT SC Sport, 4.6L, Auto, Captain Chairs, Class III Towing Package, Sliding Rear Window,
White, 4X2, CD, K&N Filter
More to come

 

I have not burnt the first tank out since the replacement yet. I don't expect to see improvement on the first tank since I have been a little heavier on the pedal to hear the sound on take off.

I will mention a difference I found in gas though. Running a few tanks of no-name gas always yielded 15.2 to 15.8 MPG on average city/hwy driving. First tank of the medium grade Texaco got 16.8 MPG on the same type of driving. Now if I can find Texaco at the same price as the no-name...

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2000 F150 Lariat Flareside 4X2 S/C, Black/Gold
5.4, 3.55 LS, Class III, Captain Chairs, CD Changer, Sliding Rear Window
Mods: PendaLiner SR Pro, Factory Body Molding, FlowMaster

 

I got the stock muffler on my 97 SC 4.6L replaced today. Got the a Flowmaster 50 series put in and it sounds GREAT! If you want a great sound and don't want to spend alot try just replacing the muffler. I don't think you will be disappointed. I sure wasn't!