Flowmaster vs Magnaflow

[truckster]

My exhaust has finally rusted out to the point where I can't stand it anymore. I'm thinking of building my own system from 2.5" 304 stainless. I have an L31 Vortec running about 9.5:1 compression and 2.5 Corvette-style rams horns. I plan to have the exhaust exit behind the rear wheels.

I really like the sound of the exhaust on my 95 Z/28; I want something with some serious growl but not necessarily obnoxiously loud. I've listened to a lot of YouTube clips and I think I've narrowed it down to Flowmasters or Magnaflows. I'd love to hear your feedback.

[Louisvillekytruck]

Flowmaster

[72SB]

FlowMaster are a chambered muffler that bounces sound vs MagnaFlo which is a "straight through" type (slight S curve perforated pipe wrapped in fiberglass)

Flow Master 40's are the old school muscle car sound but are on the loud side.

MagnaFlo has more a low end tone but not as loud

a straight through aka "Turbo" muffler vs chambered muffler will produce more HP

I had FM 40's on my 67 Camaro. The loud interior noise on Fwy was more than, at my age now, I want. I got the new FlowMaster FX muffler which is a "turbo" type, not chambered. Maybe FlowMaster wants more of the Turbo muffler market also as it has not been out that long. It has more note than the MagnaFo or DynoMax Turbo mufflers and when you hammer it, you know its there. SS, welded for around $44 each. I got mine on Amazon but the usual places sell them

These are all the FlowMaster muffler types

https://www.holley.com/brands/flowma...flowfx_series/

[Richard]

If you like the Flowmaster sound would recommend the 70 series aka "big block muffler. Same great sound of the 40 or 50 series. But........very mild at idle and cruise without being to loud or obnoxious under full throttle. As far as hp loss between the two you mentioned, it is negligible in tests I have seen. A non issue for a driver IMO.

[lolcopter]

I love my thrush ultra flos (magnaflow style). Nice rumble at idle then get pretty loud when opened up. I've had flowmasters in the past, loved the tone hated the drone.

[Palf70Step]

I have had trucks with both, but I tend to side towards the FlowMasters most of the time. Best combo I have had I think were Flowmaster Delta 50s. Loud/super healthy as heck on the outside, but very mellow tone from the inside unless you are getting on it. Big thing I found to cut drone is put the mufflers as far to the rear as you can.

[Joyridin]

By any chance, did you check these out? People like Flowmasters, but they always seem to have a nasty drone. I put these on my truck and they sound awesome and seem to have more power. I ran my exhaust out the side, so I used a 300 series "quiet" muffler.

https://spintechmufflers.com/

[72SB]

^^^ for Spintech, I have them on another 383/T56 car. 3000 XL. Mellow tone and no drone. If you like a loud, aggressive sound that their Pro Streets are the ones to get

[68 P.O.S.]

Cherry Bombs

[Sheepdip]

Flowmaster Super 40's

[Old_Gold]

I've got headers and the 40 series flow masters in mine. No drone and it makes me smile every time I hit the gas!
Jim

[kwmech]

I have flowmaster on my 68 and a magnaflow on my flatbed. I like the tone of the magnaflow better

[HO455]

Flowmaster are not for vehicles that see a lot of highway miles. The drone is unavoidable (and hazardous to your hearing) unless you put some sort of Helmholtz resonator on the system. Not difficult to do but they do take some tuning to get them right.

[rockyrivermark]

Below are a few video clips of the two types of flowmaster muffler I’m running
The C10 is a mostly stock 350 other than headers , intake and carb. Stock heads and cam. The truck has a flowmaster delta 44 chamber
And “H” pipe or “X” will reduce the chance of drone

The ‘67 cougar has a newly built and installed gen one 302 with street cam, performance heads, intake etc. headers and flowmaster FX muffers (non chambered, see photo) these Flow FX’s are similar to a Magnaflow design
Interestingly the old 289 with stock cam was quiet unless you put your foot in the pedal. The cammed 302 is loud with exhaust unchanged.


I really struggled with muffler choice and happy with result so hope this helps you out.
Mark

https://youtube.com/shorts/9OvsRS8YwS8?feature=share

https://youtube.com/shorts/lFqE4VLGxZ8?feature=share

https://youtube.com/shorts/1NfnmlMhImc?feature=share

[Richard]

Have made other comments on Flowmaster posts. Stress that people need to check out the 70 series Flowmaster vs the 40/50 series. Huge difference from the 40-50 series. Many avoid the 70 due to increased cost. I get many good comments on my 94 exhaust, my wife is even fine with the tone, drone and sound level. Probably going to use two 3" 70 series with an x pipe on my current 72. Sound good to me and noise level is tolerable at all rpms. I am not worried if stand to loose a few whp vs a straight through type muffler. My truck will be a driver, not a 1/4 mile dragster where every tenth counts.

[Gregski]

having played the exhaust game for years, you can make anything sound anyway you want, don't go by what you hear on YouTube, computer speakers are different, headphones are different, iPhones are different

if you compare Vortec engines of native Vortec trucks they sound the way they sound because the mufflers sit behind the catalyitic converter and that makes a huge difference in the sound, one that is very difficult to replicate simply by using resonators, so keep that in mind, you may need to run a cat on your old rig to get the rumble sound

I personally could never tune out the drone out of my Flowmaster 40 series on my '74 and they were so loud (true dual exhaust) that my daughter would not want to ride in the truck with me

and forget about dropping the exhaust in front of the rear axle with the Flowmasters, your head will explode from that pavement pounding, ha ha

I would recommend a dime a dozen turbo mufflers and if you go dual and get the small ones they will surprise you how good they will sound at the fraction of the cost

[pontiacvince]

I put the Flowmaster 5-series on my '71 Suburban with an x-pipe I bought from Summit. My exhaust is only 2 1/4" all the way back because my lil 307 doesn't need huge pipes. I was worried about drone and resonance inside the Suburban and insulated and sound deadened EVERYWHERE. The Flowmasters are just forward of the rear axle and above the trailing arms. At idle, it almost sounds stock...until you put your foot deep into the gas. I LOVE the way it sounds!

[Richard]

Originally Posted by Gregski

having played the exhaust game for years, you can make anything sound anyway you want, don't go by what you hear on YouTube, computer speakers are different, headphones are different, iPhones are different

if you compare Vortec engines of native Vortec trucks they sound the way they sound because the mufflers sit behind the catalyitic converter and that makes a huge difference in the sound, one that is very difficult to replicate simply by using resonators, so keep that in mind, you may need to run a cat on your old rig to get the rumble sound

I personally could never tune out the drone out of my Flowmaster 40 series on my '74 and they were so loud (true dual exhaust) that my daughter would not want to ride in the truck with me

and forget about dropping the exhaust in front of the rear axle with the Flowmasters, your head will explode from that pavement pounding, ha ha

I would recommend a dime a dozen turbo mufflers and if you go dual and get the small ones they will surprise you how good they will sound at the fraction of the cost

See lots of experience with the 40-50 series, understand they are not desirable to anyone except my 20 year old self. The 70 series is no comparison.

[KQQL IT]

Depends on the engine as well.
40 series on a stock 454 sounds good.
70 series on my 73 sound better but a completely different engine. Rowdy roller cam sbc

[custom10nut]

When I bought my truck 30 years ago, it came with “Straight through” Glass Paks. I’ve always been a fan of Glass Paks for the aggressive tone they give.
In the late 90’s I needed to replace the exhaust (2 1/2 inch with H Pipe), and went with Turbo Style muffler, as that was the popular thing to do then.
I was never quite satisfied with the tone/sound of the Turbos (just me ).
This year I’m cutting the Turbos out and going back to the “Short and Fat “Cherry Bombs” that I’ve been wanting for a long time.
You might find a couple trucks, with the muffler you’re looking at, and ask to hear them.
Also keep in mind that many of the newer style mufflers are developed and designed to make Catalytic Converter equipped vehicles sound more aggressive
To each his own on this subject, but that’s my .02

[Sheepdip]

Well here is $.02 more cents worth. Building my 40 Ford Coupe 350/350 I was to the point of deciding on mufflers, I was at the March Meet in Bakersfield Ca. and Flowmaster had a booth there.

I talked to the rep and asked a simple question, "For a slightly warmed SBC application, what muffler do you sell the most of with positive feedback and or results" He did not hesitate and said "Super 40's" He also noted that a "X" or "H" pipe was a must to a proper end result tone/sound.

My 40 got Super 40's installed with an "H" pipe, and I can say it sounds really nice, and have had numerous people inquire as to what mufflers am I running.

Not all have the same taste or hear things the same, but this was my experience and could not be more pleased.

[72SB]

I agree on the point made about the exhaust note with the same muffler will be different for a stock SBC vs a camed/header SBC let alone one with headers.

My stock 327 (4 brl) with true duals to 40's then OTA pipe exit behind wheels. It had the "classic" muscle car sound.

Put in a 411 hp camed SBC crate motor and it was too loud for me, especially on Fwy. Had to talk LOUD to have a conversation.

I was going to put in a Turbo type muffler either DynoMax or MagnaFlo until I ran across the FlowMaster FX "turbo" style muffler they recently came out with. Has a good muscle car sound and barks when hitting WOT but tame during cruising. To me its best of noth worlds but exhaust note is subjective so just listen to other trucks and find out what they have if you like the sound but note "their" engine vs yours to keep it in perspective