# Exhaust help!



## awilks85 (May 28, 2017)

Hey all

I have a 1966 tripower and wanting to put exhaust on it. Debating if i should do Pypes or Flowmaster and then 2.5 or 3 inch pipes? Any suggestions on mufflers would be awesome as well. Was looking at some of the pypes set ups and looks like they have Race Pro and Violater, not sure what flowmaster offers. 

In terms of sound, i want an aggressive idle rumble and a good throaty sound when stepping on it. 

Thanks!


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## GTO JUDGE (May 14, 2005)

awilks85 said:


> Hey all
> 
> I have a 1966 tripower and wanting to put exhaust on it. Debating if i should do Pypes or Flowmaster and then 2.5 or 3 inch pipes? Any suggestions on mufflers would be awesome as well. Was looking at some of the pypes set ups and looks like they have Race Pro and Violater, not sure what flowmaster offers.
> 
> ...


IMHO: If your budget allows? Go with Gardner. 
I have pypes pro street on mine 2.5" with straight pipe. I get more compliments on the sound than I can count. It came with the car, it's aggressive. if I were to change out I'd go with the Gardner mufflers. Gardner is expensive but it's as close to factory as you'll get. I also think in my opinion, pypes has it all over flowmaster


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## PontiacJim (Dec 29, 2012)

awilks85 said:


> Hey all
> 
> I have a 1966 tripower and wanting to put exhaust on it. Debating if i should do Pypes or Flowmaster and then 2.5 or 3 inch pipes? Any suggestions on mufflers would be awesome as well. Was looking at some of the pypes set ups and looks like they have Race Pro and Violater, not sure what flowmaster offers.
> 
> ...



Just my opinion.

Assuming factory exhaust manifolds? I would go with 2.5" pipes for several reasons. First, fitment. 3" is pretty big and they will hang lower and clearance in general will be tighter. 3" pipes will be louder as you will get a little more "echo" (sound waves) bouncing around. You need a little back pressure in an exhaust system so the exhaust does not over scavenge the air/fuel mixture during valve overlap. 

Now, if you have an engine pushing over 450HP and can spin a lot of RPM's, then 3" pipes would be my choice as you want to get that exhaust flow moving. You might want to do a little mixing of your pipes like run the 2.5" head pipes to your mufflers, then run a 3" tailpipe. 

I have played around with exhaust systems with all the cars I have owned and found that the placement of the muffler also contributes to the sound that comes out. The larger diameter tailpipes can change the sound. In my time it was Corvair Turbo's we all ran. They were short and had the 2.5 inlet/outlets. Length and diameter is another factor that changes sounds as well as the baffling inside - with many having their own design.

The last set of pipes I had were a 3" dia to a pair of Dynamax mufflers and turn downs in front of the rear axle. Now I just told you not to use 3" pipes, but my thinking was that I was using the factory restrictive cast iron exhaust manifolds which I felt would developed the back pressure in the exhaust system and the 3" pipes would not over scavenge the cylinders. Problems I encountered as I fab'd up my own system was that the 3" pipes were extremely close to the oil pan (I used a 3" elbow to which I welded reducers to work with the exhaust manifold outlets) which I am sure added extra heat to the oil and they hung low like headers - and yes I did hit 'em with the "bouncy" front springs I had in the car. My Dynamax mufflers had a drone about 2,000 RPM's, BUT they now advertise "Drone-Free." I liked the sound, but again, no tailpipes. I will probably go with them again with my 455CI build.

Some muffler sites have sample sounds you can listen to. You might also try You Tube and find a Pontiac having a similar system you are looking to go with or get a few ideas of what other system's sound like. Keep in mind that the cam selection and even compression ration has an effect on the exhaust note as well. Here are a few to choose from: 



 and check out this Firebird pulling away, it sounds pretty good too:


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## geeteeohguy (Feb 2, 2008)

That '66 in the vid sounds terrible, IMO. The Firebird sounds great. I have seen very good results with 2.5" Pypes systems with a cross-over. 3" is too big and ghetto. Flowmasters are great if you like riding in a droning drum all the time. I have Walker Corvair Turbo's on my '65 (since 1991) and Midas stock mufflers on my '67 (since 1987). I like to be able to hear myself think and hear the radio when I drive. Loud, crackling exhaust gets old fast.....kind of like cards in bicycle spokes.


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## El Monte Slim (Sep 8, 2014)

*Exhaust choices*

It all depends on several factors.

1. How original, or how _modified_ is your car?

2. Do you value loud, throaty or deep?

3. How much do you want to spend?

Back in 1972 when I purchased my 66 4-barrel car from the original owner, it needed a little exhaust work. I decided to put a complete new system under the car including Corvair Turbo mufflers and 2 1/2 " pipes out the back. It sounded good. Not loud, but a deep rumble. No "popping" on deceleration. Never got a ticket for exhaust noise and it did not attract any unwanted attention from Johnny Law.

Fast forward 42 years. I was just completing a full rotisserie off-frame restoration of my all numbers-matching car. I went with Gardner exhaust to replicate _exactly_ what was under there leaving the factory. Sounds good, nice deep rumble and the resonators means it has no drone at highway speeds. That factory original AM-FM radio sounds good at 60 mph!

Not cheap, but darn well worth it to me.

I can't advise concerning any of the other aftermarket systems.

Let us know what you choose and how you like it!


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## Goat Roper (Oct 28, 2014)

GTO JUDGE said:


> IMHO: If your budget allows? Go with Gardner.
> I have pypes pro street on mine 2.5" with straight pipe. I get more compliments on the sound than I can count. It came with the car, it's aggressive. if I were to change out I'd go with the Gardner mufflers. Gardner is expensive but it's as close to factory as you'll get. I also think in my opinion, pypes has it all over flowmaster


I have a Pypes system with a crossover and Magnaflows...hanging on the wall in my garage.
I went with the Gardner factory repro system with resonators.
You can hear the cam lope at idle and it is loud when you open it up but at freeway speeds we don't have to yell at each other and I don't hear it over my stereo.
I didn't like the droning and when I started the mechanical and suspension restore the first thing to go was the exhaust.
If anyone wants it it is practically brand new since the guy I bought the car from had just had it installed.


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## mgrablin (Sep 23, 2014)

I went with the Gardner Concourse correct system with the high flow mufflers on my numbers matching 67 GTO. It sounds great at idle and on the road. I can't figure out how to get a video to attach. 



Sent from my iPhone using Tapatalk


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## GTO JUDGE (May 14, 2005)

Goat Roper said:


> I have a Pypes system with a crossover and Magnaflows...hanging on the wall in my garage.
> I went with the Gardner factory repro system with resonators.
> You can hear the cam lope at idle and it is loud when you open it up but at freeway speeds we don't have to yell at each other and I don't hear it over my stereo.
> I didn't like the droning and when I started the mechanical and suspension restore the first thing to go was the exhaust.
> If anyone wants it it is practically brand new since the guy I bought the car from had just had it installed.


Mine had the X-pipe on it when I acquired the car, it was not installed in a proper location and hung down because of the location of it with the transmission pan, it looked terrible from the side and would scrape the ground on occasion when navigating speed bumps or going up a grade then to level ground. I had it removed down pipe slightly altered, and straight pipe installed, It drones at about 30 mph. It does announce the Ram Air IV cam I have in it nicely at idle and when stomping on it. I've heard many different exhaust tones on goats and IMO next to Gardner, Pypes on a Pontiac engine sounds best to me.


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## Goat Roper (Oct 28, 2014)

That x-pipe transmission heater is about the stupidest thing I have ever seen on a car.
If anything you want to add a cooler to the tranny not a heater.
Dragging it on aprons and over dips in the road is just another reason not to go this route.


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## El Monte Slim (Sep 8, 2014)

*Gardner Exhaust*

I've attached a few photos of the Gardner Exhaust System when it was installed under my 66.


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## Goat Roper (Oct 28, 2014)

Very nice!

Here is a sound clip of a '67 with my system.

http://www.gardnerexhaust.com/soundclips/67GTOResSnd2.mp3


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## 1968gto421 (Mar 28, 2014)

Looking at the pics of the Gardner systems, its hard to tell. Does Gardner use mandrel bends or the "pinch" bends that the corner muffler shop uses?


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## SSnakeAce (Sep 18, 2014)

I'm probably the odd ball out, being young and still quite happy with loud exhaust.

On my 67, I went with a custom system, running RARE oversized ram air manifolds, with full mandrel bent 2.5" exhaust, no crossover, and dual 8" Cherry Bomb glasspacks. It's certainly not quiet, but it's not ear-bleedingly loud either.

You can hear a couple of vids over at my other topic at http://www.gtoforum.com/f12/finally-road-again-116937/index2.html#post797249


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