Need some opinions on Flowmaster mufflers

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
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Long Island, NY
Does anyone have a part number for the [old] dynomax muffler?

If not, maybe a PDF of an old catalog that had them listed or something?
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not sure if this will help. All I had from my old catalogs.
 
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DannyB1122

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Sep 17, 2012
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I have Dynamax on my 87 GT Convertible courtesy of the last owner, who, for some reason, took the original Flowmasters off. They sound good when the car is running when parked, but absolute torture on the road since the sound basically drowns everything out that's going on inside the car. Like one of the earlier posters said, YouTube is a good place to start. I think I'm going to end up switching to Super 44s or something that gives a good sound outside the car, but doesn't kill your eardrums inside.
 

MustangIIMatt

Easy there, this ain't a dating site.
15 Year Member
Mar 7, 2002
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I have Dynamax on my 87 GT Convertible courtesy of the last owner, who, for some reason, took the original Flowmasters off. They sound good when the car is running when parked, but absolute torture on the road since the sound basically drowns everything out that's going on inside the car. Like one of the earlier posters said, YouTube is a good place to start. I think I'm going to end up switching to Super 44s or something that gives a good sound outside the car, but doesn't kill your eardrums inside.
If you think Super 44s are going to drone less than anything Dynomax puts out, you're gonna have a bad time. I've run Dynomax Super Turbos, Ultra-Flows, and their Flowmaster knockoff chambered mufflers (Thrush Welded), and they all drone less than my Super 44s.

My Flowmaster Super 44s were ironically the best sounding mufflers I've ever had on a 5.0, and I mean that, they sounded damned amazing, but the drone at cruising speeds was so terrible that they had to go.
 
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Willybill32

But at least it's tight!
Jul 16, 2019
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Lexington, KY
Hey guys, I am looking at replacing the magnaflow mufflers on my car (1990 Mustang 5.0 convertible with aod) with flowmasters. Everything else on my car is completely stock. I love the sound of the Flowmaster original 40 series, but I read that the drone is aweful. I'm looking at either the Flowmaster Delta Flow 40 series (which sounds close to the original 40 series, but without the excessive drone from what I read) or the Flowmaster Super 44 (which has a slightly different tone then the 40 series). I wanted to know if anyone is running these mufflers and if you can share your experiences.
Thanks,
I have a second set of Flowmasters on my '86 GT presently. The current set was part of a Flowmaster cat-back system, and I think they're 40s. When it was stock, I was OK with the sound, but with some performance mods to the 5.0, as well as Bassani shorties and Bassani catted X-pipe, I now find the noise level really bad. I'll add sound deadening to the floor when I replace the carpet, and if that doesn't help, I'll be looking for something quieter.
 

Middleagecrisis

Active Member
Aug 23, 2020
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If you lived in central Texas, I'd swap my catback with Flowmasters on my '93 GT with you. Sounds good at idle, but I hate the highway drone. Like everyone says, it's all a matter of preference.
 

Dan02gt

10 Year Member
Mar 2, 2003
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Greenville, NC
let me put that into perspective.

” I have crotch rot,...but I only notice it when I wear my tight pink panties...So,...most of the time I don’t wear my tight pink panties, and it doesn’t really bother me.”

Lol you got me. So Ok.
I had a ‘96 GT with a off road h pipe and Flowmaster original 40s. I put 50k miles on that combo and loved it. I had a ‘02 GT with a off road h pipe and 40s that I put 35k miles on and loved it.
I had a ‘06 GT with a off road h pipe and the supper 40 or 44 Flowmaster axle back. Now that sob was loud and had tons of drone and I hated it. I swapped the off road h pipe with a off road ProChamber and that dropped the sound down significantly and cut out most of the drone. I put 32k miles on that combo.
When I bought my ‘11 GT my life had changed. I was 31 and was taking 800 mile road trips on the regular with my girlfriend and neither of us wanted to hear that loud of exhaust for that long so I put a GT500 axle back on it and called it a day.
My fox came with a off road h and Dynomax Super Turbos. Sounded great with a stock engine. Not overly loud and little drone. When I put the AFR heads on I hated the way they sounded so I swapped them to Flowmaster Delta 40s. I like the sound much better, but it’s a little loud for my taste at 41 now. So my next plan is to install cats to tone it down and clean up the exhaust smell. My fox is a nice weather toy and doesn’t get driven much. If I drove it everyday I would still have the 40s I would just be more in a hurry to do something with the mid pipe.

If OP still has the stock h pipe his car will be nowhere near as loud as mine with whatever muffler he goes with.
 

Titanium90

Member
Mar 11, 2019
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Milton, Ontario
Lol you got me. So Ok.
I had a ‘96 GT with a off road h pipe and Flowmaster original 40s. I put 50k miles on that combo and loved it. I had a ‘02 GT with a off road h pipe and 40s that I put 35k miles on and loved it.
I had a ‘06 GT with a off road h pipe and the supper 40 or 44 Flowmaster axle back. Now that sob was loud and had tons of drone and I hated it. I swapped the off road h pipe with a off road ProChamber and that dropped the sound down significantly and cut out most of the drone. I put 32k miles on that combo.
When I bought my ‘11 GT my life had changed. I was 31 and was taking 800 mile road trips on the regular with my girlfriend and neither of us wanted to hear that loud of exhaust for that long so I put a GT500 axle back on it and called it a day.
My fox came with a off road h and Dynomax Super Turbos. Sounded great with a stock engine. Not overly loud and little drone. When I put the AFR heads on I hated the way they sounded so I swapped them to Flowmaster Delta 40s. I like the sound much better, but it’s a little loud for my taste at 41 now. So my next plan is to install cats to tone it down and clean up the exhaust smell. My fox is a nice weather toy and doesn’t get driven much. If I drove it everyday I would still have the 40s I would just be more in a hurry to do something with the mid pipe.

If OP still has the stock h pipe his car will be nowhere near as loud as mine with whatever muffler he goes with.
Thanks for the response. Yes, I still have the factory h pipe. I think I will be going with the flowmaster delta 40. I just love the tone from the 40 series and with the delta, it will reduce some of the drone.
 

junkyardwarrior

Active Member
Jan 10, 2011
349
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I have 50's on my 92 gt. They are loud. Mine are 3" and fed by a 427", so that might make a difference. They are loud at idle, they are loud at part throttle, and they are loud at full throttle which basically rarely happens. But it does sound good. I'm thinking about throwing cats on it.
 

96pushrod

I think they're a little easier to get off
May 15, 2018
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Savannah
I’ve always had great experiences with the dynomax ultraflo. They don’t have any sort of drone and are quieter than my old flowmasters. They’re 3in diameter but you wouldn’t even know unless you’re wide open.
 
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Bree

Active Member
Jan 12, 2021
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I have Flowmasters. It was one of the first things I did when I got the car was a Flowmaster cat-back kit. You have already claimed to like the sound of a FM so that should be a non issue for this discussion. So can I assume something along the lines of longevity is what's on your mind? I try to keep the car out of the winter slop, and it's been in the shop waiting it's turn for 6 years, I got the car in the late 90's and they're still in good shape.
 

Rdub6

So while I wait to figure out my rear end issues
Dec 29, 2017
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Long Island, NY
I have Flowmasters. It was one of the first things I did when I got the car was a Flowmaster cat-back kit. You have already claimed to like the sound of a FM so that should be a non issue for this discussion. So can I assume something along the lines of longevity is what's on your mind? I try to keep the car out of the winter slop, and it's been in the shop waiting it's turn for 6 years, I got the car in the late 90's and they're still in good shape.
I have found that they will rust out from the inside first. I guess from the condensation of the heat/ cold cycles.
The car I have now had a set on it when I bought it, that looked to be only surface rust on the outside. I took them off, and dumped a pile of rusty metal out of both of them.
But as long as I have a fox body, I’ll have Flowmasters!! Hell, I even put a Flowmaster cat back on my F150 (but it just doesn’t sound the same).
 

mikestang63

SN Certified Technician
Aug 27, 2012
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may not matter but I have MAC SS flowpath;s on my 90 and am happy with them. On the 86 I have the ole flowmaster 3 chambers which came with the car.
 

Mustang5L5

Put lubricant all over the balls
Mod Dude
Feb 18, 2001
36,408
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Ive got a pair of OOOOOOLD flowmaster 40's from the late 90's. Maybe 500 miles on them. The only bad thing about them is the guy who cut them off cut them too close to the muffler. I need to weld a tube stubby onto them first.

Now that I have a welder, I might. Those old flowmasters have a different (better) sound than the new ones.
 

Cheapskate207

The left one hangs a little lower
Jan 12, 2020
455
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Maine
I had flowmaster 50’s on my car. I was happy with them but thought they were 40’s until this winter when I bought ultraflows to replace them. If I end up not liking the ultraflows I’m thinking about trying some 40’s.
 

Rcdgl

Active Member
Feb 19, 2018
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I have super 40s on the 82 and regular 40s on my Malibu. Love them both.
 

Neuron

Mustang Master
Nov 6, 2016
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If I can't see through them they don't get installed. Very happy with the sound acceptable drone too.

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