Have question for Magnaflow owners

[66farmer]

I ordered a pair of Magnaflow 3"x22" oval for my 66 short stepside I'm running a 454 3" pipe will exit rear of the tires not plaining on installing a H or X crossover. Well yesterday the brown truck dropped them off. I got them out of the box and the first thought I had is that is a big ass muffler. I ordered the 22 because I don't want the truck to be real loud but I think know I went to big. Could you guys that have the Magnaflows tell me what you think of them and what size your using.

Thanks for the help

[Palf70Step]

I have magnaflow on my current late model truck and had them on my 2003 Dodge. They sound good, but not over intrusive on the inside. Personally, I liked the FlowMaster 50s I had on my 96 better, but it was a more noticeable inside the truck. not loud, but way more noticeable than the MagnaFlows.

[Corts60]

I'm not sure of the exact size I had on my Nova SS (they were comparable in size to Flowmaster 40's) but I loved them. Super great tone and if you have tail pipes, there is no cab drone at all. I personally am growing more fond of magnaflows than I am flowmasters.

The exhaust sounds a bit choppy because this video was when it had a cam that didn't particularly work well.

[creep]

I have a Magnaflow system on my V6 S10 and I love the sound and when I let off the throttle I get those subtle little pops and rumbles. On my 63 I put a pair of 4" x 16" (I think) round Magnaflow mufflers and they don't muffle much at all but that's what I was going for on that truck. Still sounds awesome, or at least they did until I blew out both collector gaskets pulling out of a gas station, just really loud. Magnaflows usually start sounding better after a few hundred miles because the stuff inside them has to break in and settle. I think it's some kind of lava rock or something like that.

[BR3W CITY]

mangaflow 2.5x~20 bullet style. I think technically its a "resonator" not a true muffler. I have true duals off of my 6.0, no crossover, exits before the rear wheels out of a sharp dump. Really freaking loud, but has a great pop and rasp that makes it sound mean.

[Baby Blue 66]

I have a pair of Magnaflow 14326 (14Lx9Wx4H oval) installed in a 2.5" dual system with H-pipe that exits under the rear bumper on a mild 350. It has a nice mellow sound at lower RPM's and barks pretty good at higher RPM's. I don't have to worry about getting a headache when cruising.

[belair427]

I have owned a muffler shop for 26 years I can likely answer your question a little better with additional information. As I understand it you must have 12578, 12579 or 12589 mufflers which is a 22 X 5 X 11 body muffler. Assuming you are running headers, 3" tubing with these mufflers will still be fairly loud. If you are concerned about drone in the cab, the issue is as much related to tubing size as muffler choice.
We have tested 3 muffler brands, Dynomax Super turbo, Flowmaster 40 series and Magnaflow, in 2 different tubing sizes on a 355 drag race engine in one of my technicians 79 Malibu. For testing purpose we used the same size muffler in each brand. What we wanted to know was how much noise difference there was from one to another and here are our findings. The first test was with 2.50 inch tubing and 14 X 9 X 4 or 5 muffler (manufacturers use a 4, 4.5 or 5" thick muffler) trying to keep the tests consistant. Listed below are the decibil readings at 2000 rpms.
with 2.50 tubing
Dynomax 17733 93 db
Magnaflow11226 95 db
Flowmaster 42543 101 db
with 3.00 tubing
Dynomax 17744 98 db
Magnaflow 11229 106db
Flowmaster 43041 108db
Remember that a H pipe or an X pipe will decrease noise as well. On this car after we decided on 2.50 and Magnaflow muffler we then installed an X pipe and the sound dropped to 89db

[dmwphoto]

Originally Posted by belair427

I have owned a muffler shop for 26 years I can likely answer your question a little better with additional information. As I understand it you must have 12578, 12579 or 12589 mufflers which is a 22 X 5 X 11 body muffler. Assuming you are running headers, 3" tubing with these mufflers will still be fairly loud. If you are concerned about drone in the cab, the issue is as much related to tubing size as muffler choice.
We have tested 3 muffler brands, Dynomax Super turbo, Flowmaster 40 series and Magnaflow, in 2 different tubing sizes on a 355 drag race engine in one of my technicians 79 Malibu. For testing purpose we used the same size muffler in each brand. What we wanted to know was how much noise difference there was from one to another and here are our findings. The first test was with 2.50 inch tubing and 14 X 9 X 4 or 5 muffler (manufacturers use a 4, 4.5 or 5" thick muffler) trying to keep the tests consistant. Listed below are the decibil readings at 2000 rpms.
with 2.50 tubing
Dynomax 17733 93 db
Magnaflow11226 95 db
Flowmaster 42543 101 db
with 3.00 tubing
Dynomax 17744 98 db
Magnaflow 11229 106db
Flowmaster 43041 108db
Remember that a H pipe or an X pipe will decrease noise as well. On this car after we decided on 2.50 and Magnaflow muffler we then installed an X pipe and the sound dropped to 89db

good info right there

[66farmer]

Originally Posted by belair427

I have owned a muffler shop for 26 years I can likely answer your question a little better with additional information. As I understand it you must have 12578, 12579 or 12589 mufflers which is a 22 X 5 X 11 body muffler. Assuming you are running headers, 3" tubing with these mufflers will still be fairly loud. If you are concerned about drone in the cab, the issue is as much related to tubing size as muffler choice.
We have tested 3 muffler brands, Dynomax Super turbo, Flowmaster 40 series and Magnaflow, in 2 different tubing sizes on a 355 drag race engine in one of my technicians 79 Malibu. For testing purpose we used the same size muffler in each brand. What we wanted to know was how much noise difference there was from one to another and here are our findings. The first test was with 2.50 inch tubing and 14 X 9 X 4 or 5 muffler (manufacturers use a 4, 4.5 or 5" thick muffler) trying to keep the tests consistant. Listed below are the decibil readings at 2000 rpms.
with 2.50 tubing
Dynomax 17733 93 db
Magnaflow11226 95 db
Flowmaster 42543 101 db
with 3.00 tubing
Dynomax 17744 98 db
Magnaflow 11229 106db
Flowmaster 43041 108db
Remember that a H pipe or an X pipe will decrease noise as well. On this car after we decided on 2.50 and Magnaflow muffler we then installed an X pipe and the sound dropped to 89db

The mufflers are 12578 I want to hear the BBC I just don't want to be blasted out of the cab. The next size down are 18" I think that would be to load.
What do you think

[krazy_texan]

i had magnaflows on my all my ford rangers, and i plan to use them on both my 65 and my 67 and my lincoln as well as the time comes to do those my father swears by flowmasters but they do have more cab drone

[awbrown]

I have flow masters on my 97 silverado with a stock 454 and they exit behind the rear wheels both on the pass. side.. you do get a lot of drone in the cab even at highway speeds... Afriend of mine and I tested 3 brands of muffler on the dyno in 2003 on a 470 inch BBC .. We had flowmasters ,spintech,magnaflows and borla .. the straight thrus were within 1 hp of each other .. the flowmaster was down a couple more , but the spintechs were down by 15+hp ,but they were the quietest ones also ...