[Ben M.]

So what are people using for their exhaust these days on the bigger cars? I crawled under my '71 today (455) and found that it has dual exhaust with Flowmasters and large 3" tips welded on the ends. To say it drones and is loud is an understatement. I don't want to anger the neighbors, that's how annoying and loud it is.



Would cutting off the truck tips help in the loudness department as a temporary measure?

It seems the Dynomax Super Turbos 17749 is also the go-to muffler for many as well, eliminating drone which this car has in spades.

[jmt455]

I like the DynoMax Welded Ultra-Flow or the Goerlich Xlerator.
Nice, low rumble at idle and part throttle, but they really bark under heavy acceleration.

Both have a straight-through design that flows about 97-99% of a straight pipe.

I'm sure there are others that are made the same way, but I have hands-on experience with both of these.

Use the longest case you can fit under the car!

[aronhk_md]

Both mufflers mentioned are great...I have the Goerlich Xlerators in the trans am and eliminated a nasty drone between 2200-2500 that had existed with the spin tech crap mufflers that were on it. Not to mention they flow MUCH better. My Grand Prix is getting a set of the Dynomax's mentioned though...managed to pck up a pair that had been used a few weeks for almost half price. Goerlich is an OEM manufacturer and they are quiet. Just so happens they perform too. Dont think the tips will make any difference.

[David Brown]

I guess it's all what you want and like. I bought a very nice, bone stock 1972 Chevy Cheyenne Pickup truck with Cherry Bomb glass packs and the same 3" chrome tips you have coming out the middle of the rear. The tips looked way out of place and the sound was painful. My 1972 Cutlass came with series 40 Flowmasters, and it was way too loud to carry on a conversation or listen to the radio. I switched them both to stock type free flowing muffler, as jmt said, as long as will fit under the car. When I redid my Bonneville in the early 90s, I used the stock type free flowing mufflers, but eliminated the resonators. It too droned on and was real "cool" at first, but after the drone caused a headache ever time I drove more than 15 minutes, I returned to the exhaust shop to have the resonators installed. Now you only really hear it when you're on it.

None of these cars were overly loud when they were new and they still sounded just fine when you opened the secondaries.

[2+2+3x2]

I used a complete stock Waldron's Exhaust system including resonators on my '67 GP and it sounds great, it has a little rumble to it but it's not loud. All this inside the shop, don't have the car road ready just yet. They even made the exhaust pipes a perfect fit to the stock longbranch manifolds.
Cary

[Coach]

I went with Magna Flow 2 chamber cans up front and then a pair of glasspacks in the rear where the stock resonators go ( that hanger was fun to find ). The Magna's are real aggressive, but the glass packs cut the drone and allowed it to still "bark" when I got on it.

Also keep in mind that from the factory Pontiac used two different size mufflers on there, this is part of what gives those old Pontiacs a distinct tone.

-Harry

[goatless]

I've got a Pypes X system on my Bonneville with Dynomax Super Turbo mufflers. It's actually a little too quiet for my taste, even on the Bonnie. If I were doing the system again I'd leave off the X pipe on this car, since maximum performance isn't the goal. That might give it just a bit more attitude on the sound as well.

If your system is in good shape you could just swap out the mufflers. Any turbo style muffler will be quieter than the Flowmasters. The Summit brand turbo mufflers have a decent tone at a good price. My brother has a pair on his '69 Cat.

[Ben M.]

The exhaust actually does look to be in pretty good shape. I guess the drone really bothers me and seeing those stupid tips on it makes me angry. There's a muffler shop down the street, hopefully they would understand what I ask and not charge an arm and a leg.

Do resonators really quiet these systems down? I see the big cars used them, but I've never actually experienced a car that still had them after all these years.

[jmt455]

Resonators don't really quiet the system down as much as they tune the sound and eliminate annoying vibrations. You could try adding resonators without a muffler change; they might make enough of a difference to satisfy you.

But based on your original post and my experience, you probably won't get the results you're looking for without a muffler change.

[Ben M.]

Yeah, I'm really trying to make it a quiet car. The girlfriend won't ride in it if it's annoyingly loud and I am sensitive to noise myself, I prefer my cars to be subtle and quiet. I definitely seem to be in the minority considering all the performance guys who love how loud their cars are. Especially considering it's a pretty stout 455 that flies!

Thanks for all the suggestions though!

[aronhk_md]

I agree Ben, I like it quiet too. I prefer Teddy Roosevelt's way..."walk softly, and carry a big stick". Even though thats a misquote and he actually said, "speak softly, and carry a big stick". Same idea. I like the power, which is why I love turbos, but I want it to be a complete surprise.

[Mister Pontiac]

Just glad to see you keeping the '71 alive, Ben. I sure love my 455 powered '74 in the fleet. Can't have too many!

I installed dual 2.25" on mine, with stock type 'turbo' mufflers @ my local Muffler Masters. The car isn't stone quiet like it was thru the original single system, but it isn't really loud now either. Has a subtle rumble, but still quiet enough for conversations during most driving conditions. Got nearly 20K miles on it now since the install, and I'm very pleased. Not too bad for $250 installed from the manifolds back.

Good luck!

[68lemansman]

I just replaced my entire dual exhaust on my bonnie with the pypes dynomax turbo mufflers. It still has a little rumble when driving but not loud. It is even louder when getting on it.

[David Brown]

Mine has the cross over pipe, 2 1/4 pipes and stock appearing low restriction mufflers, from Meineke. I didn't like the constant drone either, and when I added the resonators like it originally had it made a huge difference. My car has driven from south Florida to Pennsylvania, and North Carolina numerous times. If it is bothering you now, a loud drome get old real fast on a long trip.