I was looking for a recomendation on some mufflers to make a 454 quiet enough to sound almost as if it was just a stock motor in a thirdgen. Thanks.

Im assuming you arent mentioning a few things, but i think youre implying them.

So do you wanna do what youre saying?
Thats easy, put a catalytic conveter, a small y-pipe and a stock muffler behind it

OR

Do you want to make a 454 sound quiet like a stock 305, without hindering performance???

Is budget an issue?

Well, lol. I'd like to to make it quiet like a stock 305 and not to sound as if it's any special. But I'd still like to have all the same power i would have with a louder more free flowing exhaust. I don't want to spend an arm and a leg but it needs exhaust either way.

stock bbc manifolds, small y-pipe, a cat and a 3" manaflow exhaust. small duration cam yadda yadda

If you dont need dual exit tips, this is what I would do. Its pretty obvious that you dont care too much about emissions with a big block, so loose the cat.

I would get a cherry bomb, or another brand glasspack and put it where the cat used to be. 3" or 3.5" single pipe whatever you end up using. It will help dull the sound and eliminate the loud "snap crackle pop" that people like so much in the SLP loudmouth exhausts or similar. These pops will only be turned into "tin" sound in a flowmaster or similar. Plus it will be straight through to minimize restriction.


Next, look at the intermediate pipes for all catback systems. There is a big straight section a few foot long before the axle, that passes under the rear floorpan / rocker. Cut out a section of that, and use a muffler from flo-pro called the "Twister Race Muffler." I have heard this on a car with long tubes and just twisters, and they sound exactly like open headers - but with less decibles. This muffler would reduce the volume of the dulled sound that the glasspack generated. And they are pretty cheap. Moroso also sells a spiral core muffler that is real similar.


Finally, I would run a single exit tip through a flowmaster 50 series big block muffler. This will do the final quieting and tuning of the sound to make it sound like a stock muffler. It is chambered and so is the stock one. Plus it is a 3 chamber design which is mellower than a 40 or 80 series.

C5 corvette mufflers

Dynomax Hemi-Super turbo's

I dont mean to hijack this..but has anyone actually installed a 2nd muffler?...If so does it actually help quite down the exhaust without hurting performance. I have a 3.5" mufflex system with a spintech muffler and it is very loud...

I have used a glasspack (IMCO brand, not cherry bomb, but they are basically all the same) as a resonator in my last car. It really does help tune out some obnoxious noises. I wouldnt say the glasspack would make it quieter, but it definately would make a difference in the "clicks and pops" category. Another thing was, this was in a 3.1l v6 FWD monte. Having the glasspack actually made the car louder inside. It turns the high pitched raspy sound of straight piped into a lower pitched "drone".

Although, using the twister, or someting else like a Hushpower II will be different. It would actually lower the decibles.

Also, magnaflow makes Roundbody mufflers that are worth looking into. They are the same basis as a straight-thru magnaflow like all their systems use, except the muffler is round and like 4" or 6" in diameter instead of being oval like a 5x9 or something.

Thanks for the replies. But, I guess what i'm looking for is the sound of a stock 305 just at idle. It doesn't really matter how loud the exhaust is when I slam the pedal down. Would flowmaster 40's work well?

Years ago, they were called resonators.
Essentially nothing more than a second muffler in the system, usually quite close to the end of the tailpipe. Many of the big luxery cars had 'em.
Quick and dirty test.....
Take the second muffler of choice, and temporarily clamp it on the tailpipe.
Don't try and drive anywhwere, but start it up and see how you like the sound.
If you like it, find a spot, cut the pipe, and install it.

flowmaster 40's alone are not going to make a big block sound like a stock 305 at idle. It will still sound like a big block.

I have a stock 305. If I were to put a flowmaster 40 or 80 on it, it would not sound quiet at idle. So, your BBC will be alot louder than that.

I think unless you find some kind of stock muffler (like the corvette idea above) and find a way to implement them on an f-body, you are going to need more than one muffler. At least some kind of resonator inline.

a set of of 180 degree headers will even out the exhaust pulses and make it sound more tame while also producing more top end power