1. Hello I have a 68 Cutlass with a mild to mid 455. I just purchased the Flowmaster 17200 American thunder kit. It comes with the Super 40 mufflers. I'm looking for a mean idle but not get a heavy resonating in the vehicle. Any suggestions between Flowmaster and Magnaflo or any other? Thank you in advance.

 

Flowmaster sound great, but the resonating sound gets old fast.

There is a reason they are nicknamed Dronemasters.

Most manga flow mufflers I have hers have a little rumble, but are civilized enough for a daily driver.

 

Buy thrush super turbo mufflers. You'll like the sound and no drone.

 

Thank you Matt!

 

I will check those out 66, Thanks!

 

I really like Spintech mufflers. Deep tone at idle and no drone on the highway. I have the Sportsman XL on my 72 Cutlass. SpinTech High Performance Mufflers and Exhaust Products (spintechmufflers.com)

Rick

 

Magnaflow all day. I'll never go back to a chambered muffler.

 

If you ask 20 people about mufflers, you'll get 30 recommendations. (No)Flowmasters consistently rank among the most restrictive aftermarket mufflers in every published test. How they manage to do that with the obnoxious sound and droning remains a mystery, but if you want all the sound of an aftermarket exhaust without the pesky extra horsepower, yeah, use them. Walker Dynomax are a nice combination of sound, flow rate, and lack of obnoxiousness for a "mild to mid 455".

 

I have the straight through straight through Flowmaster FX 2.5" stainless steel mufflers. Basically the same as the Magnaflow but cheaper. Once I broke them, they sound awesome. Quiet at light throttle and very noticeable at full throttle with no drone.

 

I put the flowmaster super 40's on my stock 455 and I do not like at all. Part of the reason could be the stock 2-1/4" exhaust and 2" tailpipes. Not sure if I am going to replace the whole system but for sure going to replace the super 40's.

 

I have some custom 40 and I think they sound great, I also love my buddy super 10's.

 

Exhaust sound is completely subjective. For what it's worth, I've used both the Flowmasters and Magnaflows. The Flowmasters sound great. But like stated above, mine drone bad at cruising speed. When you get on them they have a nice aggressive note. The Magnaflows sound great to me just driving around. I can have a conversation in the car while driving without having to yell. But when you get on it, they have that not you're after.

 

I have the "Super 40" and have no drone at all. The "40 series" are louder for sure and probably do drone. There is also the "40 Series Delta Flow" that are even quieter than the Super 40.

Here is a link to Flowmaster Muffler selector and has sounds to compare. https://www.holley.com/brands/flowma...ered_mufflers/

 

Borla. The best.

 

X2 on what Joe said. Dynomax Super Turbo's all day long. If you don't have an H pipe you might try adding one.

 

FWIW
On my 70 455 4 speed it came with Flowmaster 40's with 2.5" pipes & stock manifolds, they do have a DRONE from at JUST 1700 rpms +- and thats about it
I'm amazed that just about everyone likes the idle & and driving sound including me

LOL your results may vary

 

Between Flowmasters and Magnaflows...no question; Magnaflows for me.

With that being said however, I've heard good things on the Dynomax/Walker's and I have a rebadged Borla setup on my Ram (Borla makes the Mopar Cat-back kit). For the Olds, I have the Summit brand Magnaflow style mufflers, but have yet to install them (finding an actual exhaust shop around here is difficult). I had them on my Dodge before I got the Olds, and between the headers, 2.5" pipe, and the fact that they dumped at the axle just behind the mufflers-that's easily the best sounding car I've ever owned. Tame during cruising, but an animal once you really get on it.

 

I have the DynoMax Ultraflows on my car. They are quiet enough for a conversation without yelling.

 

Ditto, and that right there will tell you why its one of the most popular performance mufflers in history. Yes I lifted the positives from quotes. But you will notice the positives preceded the negatives in these quotes when viewed in their entirety. For me, the mufflers positives supersede and outweigh the negatives. Nothing sounds like Flowmaster... Idle sounds ominous and wide open throttle sounds like ominous meets anger. With a violent metallic howling ping to it. I've had them on 4 different Oldsmobile's since 2001. A 67 Cutlass, A 66 442, My current 69 and my 87 442. To say I am a fan is an understatement.

P.S. if somewhat loud to loud is not your thing I do not recommend them.

 

Here is a setup in all its glory on YouTube. Credit to the uploader and his awesome car. Best to listen on a stereo setup with subwoofer, and beware of one instance of foul language. Short straight to the point clip.


The cars build. 1973 Olds Ninety Eight Regency, motor 455, C cast iron heads fully ported, ported air gap intake, ported headers,10 to 1 comp, N crank, milodon 8 quart oil pan, comp cams Xtreme Energy™, XE274H camshaft, speedpro forged slugs, 780cfm quickfuel carb, scorpion aluminum roller rockers, 3.73 posi, billet 3400 stall, 3" exhaust, super 40 flowmasters, ice cold AC, . Terry Gilomen

 

[QUOTE=69CSHC;1535289]Here is a setup in all its glory on YouTube. Credit to the uploader and his awesome car. Best to listen on a stereo setup with subwoofer, and beware of one instance of foul language. Short straight to the point clip.
, 3" exhaust, super 40 flowmasters,

Sounds awesome! One bad *** 98! The engine build and 3" exhaust sound a hell of a lot better than my stock 455, stock exhaust with the super 40 Flowmasters. I wonder how much of a difference going to 2-1/2" exhaust with stock manifolds would make?

 

Pypes. Nice and mello at idle, yet has the bark at WOT. My worthless two cents...

 

There isn't much difference between Pypes, Borla, Magnaflow, or the Chinese knock offs. They're all perforated tube, straight through, single chamber design.