I know this is going to sound strange to many on this forum, but here it goes:
I have just ordered my 8.5” GN rear axle. :bigups: Well, I figure while I have it up in the air I plan to replace the old, kind of stock (rigged up for duel) exhaust with a header back system that I had installed on another El Camino previously for about 2 months before it burned up. Anyway, I was unhappy with the exhaust noise from this exhaust and want to change the mufflers to more my liking. Here is what I think many may find strange:
I want to find the QUIETEST mufflers with the greatest flow ratings. I am in that “mid-life” age range and see no benefit to being heard ˝ mile away, not to mention I might want to listen to the stereo once in a while. I have checked out the Holley and Edelbrock web sites and they both have links to “hear” their mufflers in action. The problem is haring something on the computer and in real life is very different I am sure. I like both the Hooker Arochamber and the Edelbrock SDT mufflers, but I am leaning towards the SDT.
Anyone have any real-life experiences with either of these? Anyone have any other mufflers to suggest?
Thanks!

I recently had dual exhaust with an h-pipe installed on my '85 305 El Camino. I used the Dynomax Super Turbos and am pleased with them. Before this system I had duals into Flowmaster 40 series dumped before the rear axle. I could not stand that exhaust. My new system is much quieter but retains some exhaust note. The Super Turbos flow better than Flowmasters also.

Hooker Aero Chambers are as loud as the Flowmaster Super 44 under part throttle acceleration, in fact I would say they have even more resonance, I cant comment on the Edelbrock SDT mufflers. The Dyno max Ultra Flow has virtually no in cab resonance and was my choice for a full flow muffler. If you want something even quieter then a turbo style muffler is the way to go, they just don't have the same flow numbers.

Thanks for the replies! I did think that the Hooker mufflers sounded loud on their website...the SDT mufflers do not sound as loud. I do not want to hurt performance, but will if I have to to reduce the sound.

i heared that the x pipes are quieter than the H but im not positive my friend has an x pipe with 1 flow 40 and dumped under the car i think that if you run thoes out it would be prety quiet, becasue his really arent that loud

Wow... I have a mildly annoyed little 327 in mine that I just tossed a set of 40 mufflers off of due to resonance (seriously, "mind numbing" begins to describe it), and put a set of Aero chambers on mine. I can honestly say there is absolutely NO comparison between 40 series mufflers and Aero chambers in sheer volume until you are absolutely at full throttle, even then they're noticably quieter than the 40s I had and there's ZERO resonance. They are VERY mild at idle, quieter than my friends 302 mustang was with turbo mufflers and the 50 series flows he put on to replace them, but they sound really mean at full throttle. As for flow characteristics, well, when I held them up before putting them on, I could see through the inlet and outlet, not just light, SEE through them, this despite them having offset inlet/outlets. I had flows on my Elco and still have them on my Mustang. Needless to say, I've already priced replacing my Mustangs flows with these Aero chambers. I'll never use Flowmasters again.

realy what is the price difference.. see im looking to set of some alarms for mine lol i have drops before the back axle but i was looking at re-doing my whole system i have some headers in my qradge and then adding flow 40s ending just behind my back tire but it is $480 which will take a while what is the noise and power diference betwen the flow and aero i didnt quite undersatand ur message

Ok, first things first, if you have the mufflers dropping in front of the rear axle, or anywhere under your car for that matter, get tail pipes and finish them out the back or behind the tires. The resonance from ANY muffler is increased massively, especially in El Caminos due to that nice flat bed being a big steel resonator, the noise reflects off of the ground under the car and back up into the cars floor or bed in our cars case. Finish the exhaust and there will be MUCH less resonance, even from 40 series flowmasters. Now, if you have the exhaust already, I bought my set of Aeros from Jegs for about
$68 each here:

http://www.jegs.com/webapp/wcs/stores/servlet/product_10001_10002_26636_-1

As opposed to about $82 each for Flowmaster super 40 or 44 mufflers. A local exhaust shop I go to said he'd put them on my Mustang for about $75, or for my friends mustang, which has no tailpipes past the mufflers, could finish the system off and install Aero chambers for him for about $150. So I'm looking at about $210 total to put them on my Mustang.

Now, you said you want to set off car alarms with yours, well then your noise level is definitely the 40 series mufflers. They most certainly have that "ground pounding" affect at idle, especially with a lopey cam. Like I said though, DO NOT put these on your car without a tail pipe, you WILL regret it later. At idle and from 20-55 mph I had resonance that literally hurt my ears and gave me a headache, this will be cut down in sheer volume and in range to about 45-50 or so mph if you put tailpipes on it. Maybe even none at all. As for performance, well, think of your engine as a big air pump, the more able it is to pump air, the better it will perform. Flowmaster mufflers and others of this design use steel baffles welded throughout their case to reflect sound, but these baffles also block flow by quite a bit at high RPM, whereas Aero chambers are basically just an expansion/reduction chamber with packing around it to absorb sound and heat, which is why I could see straight through mine, since there's nothing there.

Either way, if you put headers, higher than stock flow mufflers and a full exhaust on your car, you WILL notice a huge difference in power. Have fun with it man!

ya im stoked!! i would run the new ones out behind the back tires for sure... but the mufflers ur talking about, wont they be quieter than the 40's?

In short, yes Aero chambers are quieter, especially at idle, though they are almost as loud at full throttle. It's up to you on which mufflers you want, I will admit that even though the 40s I had were too loud for me at idle, especially due to the lack of tailpipe, on both my Elco and my Mustang the 40s sound awesome at full throttle. So, when it comes to sound, if you want loud, 40s are the way to go, performance-wise they'll not be quite as good as the Aeros will, but they do sound mean! They are also a bit lighter I've noticed, by probably 5-10 pounds per muffler, likely due to the packing in the Aero mufflers.

So anyways, have fun putting the headers on man! Compared to my Mustang the Elco was a breeze to put headers on, but I still hate putting headers on... :mad:

Just a point to consider with any mufflers, the tone quality will vary from vehicle to vehicle depending on compression, camshaft,with or without a converter, pipe diameter, tailpipes and overall exhaust flow.

ya ill think ill go for the 40s i want the noise.. atleat for now.. one more question how much should my system go for i have headers so all it is is the 40s and pipes i want them to turn after the back tire? i got an estimate at 480 but that seemed high or is that right? thanks

I agree with Don that the sound will be specific to the combo. I have Aerochambers on my car and they make plenty of noise. They are not what you would call quiet at any RPM. I get some resonance between 1500 and 1800 but above that it is some sweet music. A word of warning, they will attract law enforcement.

what ones will attract the cops the 40s?

Yeah, you know that is true... a big block will put out a helluva lot of sound with any muffler really, the more cubic inches you have, the more exhaust your car pushes out and the more sound that results in. With just a 327 though, 40s were way louder than my Aeros are, so I'd imagine that your 350 would be only a bit louder. As for cost, well that depends on exhaust shop, I already said the cost I paid for the mufflers above, as to the installation, call some exhaust shops in your area and have them give you quotes, it shouldn't be too much if it's just tailpipes, if it's a whole header back exhaust, $480 is a pretty good price.

no i have headers.. ill put them on before i go get the rest put on