I'm in the process of installing Walkers on mine replacing the Dynomax's currently installed.  I'll reply when I get my car back.  Currently, the Dynomax gives me that 2000rpm drone.  I can no longer handle it.

Walker Quiet-flow3 mufflers are what MS and several others are using...

I recently swapped to Quiet Fiow # 22430.  It has a 16" body and fits the Mustang just fine.  It is only a two inch in/out but for my stock 5.0 it seems to work well.  Good idle sound,  Quiet on the road, no drone.  Presently no crossover. 

I have 2.5" Magna Flow mufflers and 2.5" pipes that turn down at the rear valance.  At highway speeds, road noise is more annoying. 

josh-kebob wrote:

Walker Quiet-flow3 mufflers are what MS and several others are using...

I'm one that is using the Walker Quietflows. Love them! MS put me onto them after I was sick of the drone.
I find the Quietflows to have a nice note at idle and when I get into it, you can hear me coming.

I may try the Flowmasters  50 series this time around.

When Dan stopped by on the way to the bash I never heard him come in the driveway.   I was looking under his car and he had the long tube headers and the same magnflow mufflers that I have.  Mine seems a lot louder.  But when he hit it in his Stang it was loud.  He does have EFI where I have a carburetor.  So I think the engine your running also might make some difference in the sound too.   Steve69 

Last edited by Steve69 (10/22/2021 8:42 AM)

MS wrote:

Steve69 wrote:

When Dan stopped by on the way to the bash I never heard him come in the driveway.   I was looking under his car and he had the long tube headers and the same magnflow mufflers that I have.  Mine seems a lot louder.  But when he hit it in his Stang it was loud.  Hi does have EFI where I have a carburetor.  So I think the engine your running also might make some difference in the sound too.   Steve69 

Definitely true. Even same engine with a 4 barrel carb sounds different than with a 2 barrel.

 
100% in agreement with that.
I have the same exhaust system on my car as I had with a 289 and you would never know it from the way it sounds.
The 289 had no idle rumble, no roar on acceleration and very  very quiet at cruise.
With the 331 the exhaust at start up and idle sounds “hot rodish”. With the hammer down the roar is noticeable but not offensive. Cruise in OD seems just as quiet as the smaller engine.
At one time I considered a custom stainless set up but at this point I have no plans on any changes.

Corresponded w/ Tenneco.com, which I believe brands Walker, Dynomax and other muffler brands, about the Walker quiet-flow mufflers (the "Cadillac mufflers") that I think MS used, which appears to be a 2-1/2" inlet and outlet muffler.  They sent me a couple of spreadsheets so I could compare mufflers.  Filtering on the basis of MS's Cadillac mufflers (Walker 21856), indicates that there is also a 2-1/4" version, which is Walker quiet-flow 21424.  This muffler has the same dimensions as MS's muffler:  Oval shape, 4-14" height and 19" body length (not including pipes), same pipe offsets, and connections, but 2-1/4" inlet and outlet.  I'm likely going to order these and install them.  Just wanted to post this info in case others like me (who aren't pushing 427 cubic inches of air thru their exhaust system) wanted the quieter sound but with a 2-1/4" inlet and outlet.  Will update post after installation.