# Quiet muffler choice ?



## Osubucks999 (Jan 28, 2016)

I'm rebuilding a 69 400 that will be approximately 375 hp. 
I plan on driving on the highway some and am looking for a muffler that performs better than stock. 
But...I'd like it to be around the stock sound....or maybe a bit louder. 

Any suggestions ????


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## 1968gto421 (Mar 28, 2014)

A while back, _Goat Roper_ gave me some good recommendations on this subject. Perhaps when he gets his GTO resurrected with NO more problems ( http://www.gtoforum.com/f170/central-virginia-machine-service-cvms-negative-review-106018/ ), he can chime in and share his exhaust expertise with you.


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## Pinion head (Jan 3, 2015)

The best flowing near stock length case mufflers, which are quiet, are the long case (20" case) DynoMax Super Turbo's. Tom and Jim Hand proved this years ago with extensive muffler tests and no competitor has been able to outflow and "quiet" them. Do a web search, the Hands came to that result with the side/offset side 2.5" 20" case 17749. Not a surprise, the Walker DynoMax series long case mufflers have held the high flowing/quiet standard since first introduced in the early '90's. Still have for my Pontiacs, several remaining pair of 2.5" side/center 20" case Super Turbo's I ordered in the 90's. Unfortuately, the 2.5" side/center configuration was discontinued. you may be able to buy that long case muffler and configuration in a 2.25", or as an ultra flow stainless version. For a while, the high flow quiet 20" case 2.5 side/ center muffler was avail through Thrush, while Walker's sub line. Not sure if Walker still owns Thrush, but today's Thrush's Hush Thrush largest case mufflers are 18.5", not the prev 20" version.


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## geeteeohguy (Feb 2, 2008)

X2 on Pinion's opinion. I've been running the Walker Turbo's on my '65 since about 1991....still going strong. Don't know if they're 'dynomax', but they are the 2.5" with the long case. Not too loud,and bulletproof. Absolutely hate the sound of Flowmasters on these cars.


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## Osubucks999 (Jan 28, 2016)

Thanks for the info guys. 
I'll check those out.


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## 1968gto421 (Mar 28, 2014)

geeteeohguy said:


> X2 on Pinion's opinion. I've been running the Walker Turbo's on my '65 since about 1991....still going strong. Don't know if they're 'dynomax', but they are the 2.5" with the long case. Not too loud,and bulletproof. Absolutely hate the sound of Flowmasters on these cars.


X2!! Despite the company's alleged tech expertise on exhaust flow and all its nuances, a Flowmaster, whether short or long, is the WORST:frown3: sounding muffler I've ever heard in my 55 years of "gearhead-ing". Mostly around here, it's only late model trucks with them, no real cars like GTO's, etc.

I will stick with Pinion's thoughts on this matter myself.:thumbsup:


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## PontiacJim (Dec 29, 2012)

I ran the DynoMax on my '68 Lemans with the 400CI in it, mild build, and ran 3" pipes to the muffler, and turn downs just in front of the rear axle. Nice sound, but, it had a "drone" around 2,500 RPM's which others have also mentioned. Run a little below or above this RPM, and it's gone. For me, it was great as I would purposely run at 2,500 RPM's in second gear ( 3-speed stick) cruisin' down the main avenue on a Friday/Saturday night just to see heads turn - they heard me coming down the street and isn't that what its all about?


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