Need to quiet down our 484 FE...

[CV355]

Right now I am running REF headers, a Magnaflow X pipe, and Magnaflow Street-Series mufflers (straight thru design, not chambered).  I am considering some quieter mufflers, but I'm curious if this has any effect on the amount of perceivable header ping.  I'd really rather not have to change out those headers if I can avoid it.  It's louder at the engine bay than behind the tailpipes at idle.  Younger me wouldn't care, but older me needs something quieter so I don't feel guilty firing it up on a Saturday morning.   

I'm struggling to understand the sound dynamic difference between this and other cars I've built over the years.  I had a cammed GT500 with long tube headers and a similar exhaust setup, and the engine bay was quiet by comparison.  I imagine the wall thickness was greater on those Kooks headers than the REFs.  All of the sound was behind the car.  That's what I'd like on the Mach 1.

If I just swap out the mufflers for something quieter, do you think it'll get me what I'm looking for, or should I start looking for a different set of headers or exhaust manifolds? 

[Tunnelwedge]

I have my 482 choked down pretty good.
Old Small Hookers, 2 1/2" Heavy wall steel pipe with mandrel bends and two welded Thrush chamber cans
all the way past the valance.
It's still really loud.
If you find a quite switch that you can buy I'm all in.

[Gaugster]

I wonder if wrapping the headers would change the engine bay sound enough to be more "pleasant"? I've wrapped mid-pipes on various vehicles. There's some change in sound but I couldn't classify is as more quiet. Just different.

[galaxiex]

Coolest sounding street car I ever witnessed was a 71 Mustang with a very stout 351C.
It had long tube headers (don't know what brand etc) and full chambered "stock type" mufflers.
Full length system.

At idle with a slightly rumpity cam it sounded awesome!

You could hear the headers slightly "ring" with each exhaust pulse if you knew what to listen for,
and out back was a quiet rumble.
Not offensive at all.

A close second was my 69 Cyclone CJ with a brand new OEM replacement exhaust system.
When I got the car in the late 70's the original system was rotted out, and not knowing any better...
I ordered a complete system from the manifolds back from my local Ford dealer.
Still had the CJ exhaust manifolds on it.

The exhaust note was "just right" but minus the header noise.
Again, a quiet rumble that never got offensive even when the loud pedal was on the floor.

[TurboChris]

I have Hooker comps on my 427. I had flowmaster 40's and electric cut outs. It was pretty loud. My biggest issue was the cutouts would start leaking after a couple minutes after you closed them. Then you'd open and close them again and a couple of miles later they's start leaking again. I finally bought a set of Varex X Force electronic mufflers. They an outfit out of Australia. I'm pretty darn happy with them. When closed, they are quieter than the Flowmasters by about 25% (if i had to guess) and when open they are slightly louder than the flowmasters were. And of course you can either use a supplied remote control or an app on your phone which is what I use.

It's perfect for me because when I leave for the local Cars n Coffee at 7am I don't want to bother the neighbors and I feel that this is about as quiet as it could possibly be and I've had no complaints. If anything I wish it was a little louder when open. If I could find a set of electric cutouts that absolutly didn't leak I'd install those as well.  Here's a video of them closed.

https://youtu.be/v2mzYmfb0Nk?feature=shared

[CV355]

I have Hooker comps on my 427. I had flowmaster 40's and electric cut outs. It was pretty loud. My biggest issue was the cutouts would start leaking after a couple minutes after you closed them. Then you'd open and close them again and a couple of miles later they's start leaking again. I finally bought a set of Varex X Force electronic mufflers. They an outfit out of Australia. I'm pretty darn happy with them. When closed, they are quieter than the Flowmasters by about 25% (if i had to guess) and when open they are slightly louder than the flowmasters were. And of course you can either use a supplied remote control or an app on your phone which is what I use.

It's perfect for me because when I leave for the local Cars n Coffee at 7am I don't want to bother the neighbors and I feel that this is about as quiet as it could possibly be and I've had no complaints. If anything I wish it was a little louder when open. If I could find a set of electric cutouts that absolutly didn't leak I'd install those as well.  Here's a video of them closed.

https://youtu.be/v2mzYmfb0Nk?feature=shared

Do you hear more volume from the tailpipes or the engine bay?  Our Mach 1 is ridiculously loud in the engine bay- all from the headers I suspect.  The exhaust note is minimal except under load.  I even have 2 layers of sound deadening in the cabin (including thick MLV) and it's unbearable.  This is coming from a guy who used to drive with a 5" exhaust sticking out the front bumper on another Mustang, straight dump from a 91mm turbo.  I know loud.   

I'm debating putting much quieter mufflers on, but I can't imagine that would have any effect on the engine bay.  Standing in front of the car is significantly louder than standing behind it at idle. 

[CV355]

I wonder if wrapping the headers would change the engine bay sound enough to be more "pleasant"? I've wrapped mid-pipes on various vehicles. There's some change in sound but I couldn't classify is as more quiet. Just different.

Not sure.  I have wrapped exhausts before and didn't notice too much of a sound difference.  I can see it helping reduce the ringing noise, but it's more of the exhaust pulse expansion that I hear towards the engine bay.  Those REF headers are thin wall.

[TurboChris]

Yeah, it sounds like it may be your headers? I would have never guessed such a thing. You can hear in the video I posted....I rev it to about 3000 rpm while standing over the engine, you can actually hear the fan over the sound of the motor. So no, it's def lounder at the tail pipe than at the motor.

I have Hooker comps on my 427. I had flowmaster 40's and electric cut outs. It was pretty loud. My biggest issue was the cutouts would start leaking after a couple minutes after you closed them. Then you'd open and close them again and a couple of miles later they's start leaking again. I finally bought a set of Varex X Force electronic mufflers. They an outfit out of Australia. I'm pretty darn happy with them. When closed, they are quieter than the Flowmasters by about 25% (if i had to guess) and when open they are slightly louder than the flowmasters were. And of course you can either use a supplied remote control or an app on your phone which is what I use.

It's perfect for me because when I leave for the local Cars n Coffee at 7am I don't want to bother the neighbors and I feel that this is about as quiet as it could possibly be and I've had no complaints. If anything I wish it was a little louder when open. If I could find a set of electric cutouts that absolutly didn't leak I'd install those as well.  Here's a video of them closed.

https://youtu.be/v2mzYmfb0Nk?feature=shared

Do you hear more volume from the tailpipes or the engine bay?  Our Mach 1 is ridiculously loud in the engine bay- all from the headers I suspect.  The exhaust note is minimal except under load.  I even have 2 layers of sound deadening in the cabin (including thick MLV) and it's unbearable.  This is coming from a guy who used to drive with a 5" exhaust sticking out the front bumper on another Mustang, straight dump from a 91mm turbo.  I know loud.   

I'm debating putting much quieter mufflers on, but I can't imagine that would have any effect on the engine bay.  Standing in front of the car is significantly louder than standing behind it at idle.

[gregb]

An x-pipe adds an extra “tick”……,,

[mbrunson427]

I don't have any good videos, but we have the same setup on the '67 Mustang. REF's, X-pipe. It's nothing like you're describing. Definitely louder than stock, but the noise level isn't much different than when the car had FPA tri-y headers on it and an H-pipe.

I'm not certain what mufflers these are. We asked the exhaust shop to make it sound acceptable and streetable and this is what he chose.

https://www.youtube.com/watch?v=USdS3deCBC4
https://www.youtube.com/watch?v=nWn1tm4IdtE

[Tunnelwedge]

I think I have found the noise problem. I forgot to put the mufflers back on. 

https://www.youtube.com/watch?v=LbgTW8R-s08

[Stangman]

That’s funny Howie...

[Diogenes]

It would be interesting to see the difference in power levels between a quiet muffler and existing headers set up, and then full flow mufflers with a "good" cast iron manifold. Just thinking out loud....

[cammerfe]

Don't feel bad. I once, many years ago, did a tune-up for a friend. Chrysler product with the huge fins. Got it all back together, and it wouldn't start. I went over it for close to an hour, including removing the diz cap multiple times. Finally noticed the brand new rotor laying over on the fender. Put it in and it started right up

KS

(On further examination, I see I should have looked to see who the  OP was )

[Tunnelwedge]

I don't have any good videos, but we have the same setup on the '67 Mustang. REF's, X-pipe. It's nothing like you're describing. Definitely louder than stock, but the noise level isn't much different than when the car had FPA tri-y headers on it and an H-pipe.

I'm not certain what mufflers these are. We asked the exhaust shop to make it sound acceptable and streetable and this is what he chose.

https://www.youtube.com/watch?v=USdS3deCBC4
https://www.youtube.com/watch?v=nWn1tm4IdtE

Nice Car!
I noticed you don't have the right side torque box. But you have the chassis stiffener?
I consider that a must have for a high HP road car more so than the chassis bar.
Everything to stiffen the front steering.