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12 Posts
Discussion Starter #1
Wondering what options are out there to make a 4.6L sound like a V8?

My preference would be to go with something from Maganflow since I have had great results in the past (fit and sound).

My intent would be to simply cut off the stock mufflers and bolt-on a replacement. Not looking for any real performance gains, just trying to find something that sounds like an American V8!



1,129 Posts
there's a nice sticky at the top of this subforum. :gotsearch

Also, you will likely not get the same answer from multiple people, everyone has a different opinion on exhausts. Mine is a true dual ART exhaust off kooks headers, ceramic spun carsound cats, into a magnaflow x-chamber mounted mid body. I personally think it's too loud, especially when it's 2 feet from the garage wall and it shakes the room above the garage.

12 Posts
Discussion Starter #4
I have waded thru a ton of threads (thanks for the link above) and I know exhaust questions are VERY subjective since it is based on preference...

I guess my question should have been a lot more specific. Based on the location of the stock mufflers, does anyone have part numbers for some direct bolt-on replacements?

I've noticed the number of options seems to be dwindling as these cars age (items not made anymore). Again, the personal preference would be Magnaflow but the goal is the improve sound with a simple (no welding or fabrication) muffler swap.



145 Posts
What about this RMC?

It's an inexpensive mandrel bent cat back system. It would make a nice stock replacement system that should sound better than stock. On that same linked page, there is a Flowmaster system for 3.8 and 5.0's that should be fairly easy to adapt to your car. The only problem with these is they are not true dual exhaust systems. Thats what most guys on here are looking to upgrade to.

118 Posts
Selecting a muffler is subjective- All of which use packing material which although is not fiberglass (as no one has used in 20 years), they each use a sound material absorbing design (with the exception of FlowMaster which uses plates to deflect/kill sound). Even conventional "glass packs" are proven in flow testing to out perform many of the so-called "Free Flowing Real Mufflers". For reference, WyoTech, Hot Rod Magazine has numerous published articals on this. On the net, please read: (Independently tested cfm flows of the more popular mufflers, glasspacks and resonators @ 15” wc:
2 ½” diameter straight pipe 521
2 ¼” diameter straight pipe 365
2” diameter straight pipe 283
2 ¼” diameter tailpipe 268
2 ¼” round glasspack- no louvers 274
2 ¼” round glasspack- with inward punched louvers 133
2 ¼” round glasspack- inward punched louvers/installed backwards 141
2 ½” inlet/outlet Dynomax SuperTurbo 268
2 1/4” inlet/outlet Thrush CVX 260
2 ½” inlet/outlet Flowmaster 2-chamber 249
2 ¼” inlet/2 ½”outlet Cherry Bomb turbo 249
2 ¼” inlet/outlet Flowmaster 3-chamber 229
2 ¼” inlet/2 ½”outlet Maremount Super C (OEM Replacement) 149
2 ¼” inlet/2” dual outlet Maremount 183
2 ¼” inlet/outlet California Turbo 229
2 ½” inlet/outlet Hooker Aerochamber 324
2 ½” inlet/outlet Hooker MaxFlow 521
2 ¼” inlet/outlet Maremount Cherrybomb Vortex 298
2 ½” inlet center/outlet offset Borla Turbo 373 (this is an in-depth article that tests not only the mis-conception of flow demand but also how placement of a muffler (a glass pack in this dyno test) can actually "fool " the system into thinking that it is essentially a straight pipe.

I have listed here a muffler shootout test done by CAR CRAFT:

The Mufflers
SUMMIT Turbo 630125 $14.75
THRUSH Magnum Glasspack 24214 $16.50
THRUSH Boss Turbo 17718 $23.95
HOOKER Competition 21006 $25.95
DYNOMAX Super Turbo 17733 $28.50
DYNOMAX Race Magnum 24215 $31.95
HOOKER Super Competition 21106 $35.95
SUMMIT Fully Welded 630325 $38.69
FLOWTECH Afterburner 50322 $39.95


MUFFLER Flow at 28-in H20
DynoMax Race Magnum 528.64 cfm
Thrush Magnum Glasspack 507.40 cfm
Summit Fully Welded 343.38 cfm
Flowtech Afterburner 342.20 cfm
DynoMax Super Turbo 333.94 cfm
Hooker Competition 232.46 cfm
Hooker Super Competition 320.96 cfm
Summit Turbo 331.16 cfm
Thrush Boss Turbo 297.36 cfm

DynoMax Super Turbo 89 123
DynoMax Race Magnum 94 133
Flowtech Afterburner 92 124
Hooker Competion 92 122
Hooker Super Competion 90 125
Summit Turbo 89 124
Summit Fully Welded 92 125
Thrush Boss Turbo 90 123
Thrush Magnum Glasspack 92 128

All mufflers were dyno-tested on a 355-cube SBC with 10.0:1 compression, Air Flow Research 190 aluminum heads, a CompCams 292 hyd. a Victor Jr. intake, a Holley 750-cfm double-pumper, and 1 5/8 Headman headers.

MUFFLER HP TORQUE 2,500-6,000rpmAverage
Hooker Competition 397.4 381.1 286.8hp/351.9 lb-ft
Thrush Boss Turbo 407.1 384.9 292.1 hp/357.5 lb-ft
DynoMax Race Magnum 409.5 394.3 298.8 hp/366.9 lb-ft
Flowtech Afterburner 409.7 391.2 294.8 hp/361.7 lb-ft
Thrush Glasspack 409.5 389.8 297.7 hp/365.3 lb-ft
Summit Turbo 411.5 386.3 291.5 hp/357.4 lb-ft
DynoMax Super Turbo 412.7 387.2 292.6 hp/358.6 lb-ft
Hooker Super Comp 413.8 387.2 292.8 hp/359.0 lb-ft
Summit Fully Welded 415.4 390.7 295.6 hp/362.4 lb-ft

While there are mufflers that will out flow a glass pack design, it also depends on the design. Does the glasspack use "louvers or perforations" - Louvers reduce the flow by as much as 50% but Allied resonators (that sell for $20-$40) each and available at any muffler shop) installed backwards in independent test flowed 90%+ of a "race spec muffler". Others using other brands consistantly showed similar results.

Exhaust Drone
Exhaust drone & exhaust noise while both are different by definition, both are created as a result of impactors/promoters. Exhaust drone is that which is caused by harmonics- a soundwave generated which in essence takes the exhaust sound and sends it back up the exhaust system (towards the engine) and is released or transferred into the passenger compartment. This transfer typically happens where large contact areas exist that have little to no sound dampening qualities and/or materials- as a result of the muffler construction or vehicle manufacturer.

Exhaust Noise (in passenger compartment) is what most people actually complain about. While harmonics do play a contributive role, it is not the primary cause.


I would love to tell everyone that “x” is the cause 99% of the time for exhaust noise complaints, but it is typically a series or combination of numerous factors which leads or develops the level of noise which is uncomfortable to the ear. The first “rule” of an exhaust system is that the noise should be generated at the point of discharge (ie tailpipe tip). Obviously, if the tip terminates at your door or immediately under the passenger compartment, the sound level will be much greater at the exhaust discharge point than if the tip exits the rear of the vehicle, but this is common sense.

Assuming that there are no exhaust system leaks and isolators are correctly installed at all mounting points, what is not acceptable by industry standards, is when an exhaust system has been installed correctly, exiting well past the passenger compartment to have substantial exhaust sound transfer into the passenger compartment at a level which does not allow a person to talk without raising their voice to well above ambient noise levels. Whether you love to hear your engine roar (which I do), stereo blast or have a conversation, this interfers with your ability to enjoy what you like.

Now for the Causes

The first problem is most muffler shop staff today have little to no knowledge of exhaust systems, the “tricks” to installing a system that will “please” the customer, and simply verbally repeat the marketing materials provided to them by the system manufacturer. As previously noted by several others, there are 3 basic muffler designs, Absorption, Diffusion, and Chamber (Resonator), no matter which one suits your ear best, the criteria for promoting unnecessary in-cabin noise is the same.


Exhaust system material thickness should be no less than 16 gauge- double-walled pipe was commonly available through the 1970’s until manufacturers began seeking ways to reduce costs. Many of the “Muffler Chains” who marketed lifetime warranties always used double-walled pipe before “stainless steel” became the “in-crowd”. If a shop had it available, I would choose double-walled aluminized coated steel or 14 gauge stainless steel (depending on environmental conditions or personal tastes) - it is very quiet, solid and in terms of costs, pipe is pretty cheap, depending on length, 16 gauge aluminum coated runs about $11 to $20 wholesale (depending on diameter), stainless about double for the same gauge.

The muffler should be located as close to the axle (far away from the passenger compartment) as possible, allowing at least 3” of straight run pipe before a bend occurring (if installed to the forward position of the axle), with the overall length as long as possible. In the oem location, 24" will fit fine, located at the head pipe, 30" will fit fine as well and eliminate almost any possibility of drone in this particular location due to the size, length and insulation qualities (and yes, Allied does make units this long).

With regards to the 5.4/4.6 engines, The head-pipe (the pipe installed in between the exhaust manifold and the muffler) should be no greater in inside diameter the 2 7/8”, at 3” it now becomes a contributor.

Duel Tailpipes should be limited to no greater than 2.25” inside diameter, single tailpipes 3” maximum inside diameter- tips which are larger can certainly be installed but should be limited to 12” in length and have a discharge point past any material that may “catch” a soundwave or exhaust. When you exceed these diameters, it now becomes a contributor.

Tailpipe length in general should be as short as possible, minimal bends, etc, terminating past the axle, 1.5" past the body or bumper. Lengths greater than 4 feet promote “drone” (ie harmonics), typically about 3 ½ feet past the muffler.

Pipe diameter reduction should occur before the muffler. While many muffler installers like to use mufflers which reduce pipe diameter or split the exhaust at the point of discharge at the muffler, or install reducers to connect the tailpipes after the muffler induces “noise”.

Ultimately, it is the quality of the material and the installer which 90% of the time leads to a successful installation. I would like to also emphasize that it is not necessary to spend a fortune on a muffler ($100+) or system to have an excellent sounding, performing and long lasting result.

110 Posts
My personal opinion is, nothing beats the Flowmaster sound. They have many different variations of "loud" also. I did Magnaflow and Flowmaster on a few Tbirds over the years and I really love the Flowmaster sound, especially with a build engine. Good luck with your search, Brian.

1,916 Posts
I'm putting a new exhaust on my 97 4.6 Thunderbird. I have a leak between the cat and the Y pipe.

I'm planning on the do it yourself x pipe setup I've seen on this board, 2.5" with high flow catalytic converters and dynomax super turbos. I have NO idea what this will sound like, and the thread with all the clips has a bunch of dead links in it.

Anyone got an idea what this will sound like in the cabin at regular driving speeds (35mph to 75mph)?

I want it to sound "rumbly", but not be obnoxious with lots of resonance, etc. Should I get a dual in/dual out resonator for in the middle vs. the xpipe? I basically like the car being nice and quiet at highway speeds, but want a better flowing exhaust to match the PI heads and intake.


241 Posts
remove the mid resonator and replace it with a larger gave my car an aswome growl, sounded as good as any aftermarket system, but it did have a few pops aftewr u let go of the throttle but other than that it was great sounding..
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