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Discussion Starter · #1 ·
So as some of you know, my 69 "went under the knife" back in November to fix the rear main and put on my flowtech headers. The shop couldn't get the exhaust finished so I've been sporting open headers since dec18. It's been quite cool and annoying at the same time. I bought a set of Hooker turnout collector mufflers because I thought I would like the sound after watching a couple videos. Well, I don't. They are just too darned quiet! My original exhaust consisted of cast manifolds, 1 7/8 pipe and Walker stock style mufflers dumping at the rear axle. These are more quiet than the factory exhaust! I ran from my headers with 2 1/2" midpipe, clamped a header reducer to the end of the mid pipe and bolted these on dumping right on front of the rear axle, just like the original exhaust was. I don't get why this is so quiet! It sounds like it just rolled off the showroom floor! That was a lot of work to run all that pipe laying on my back in the driveway trying to beat the snow storm coming! I was so excited to fire her up thinking it would be deep and throaty... Alas, it is quieter than my 4 banger Jeep!!!

Well, good thing is I have a extra set of collectors and a set of 28" long thrush glasspacks that I can use instead of these. I really like how I can see that big ass chrome turndown through my rear wheels but if l want it to sound mean, they have to go...

 

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Maybe try some Pypes Violators, I have Race Pros with manifolds, x pipe and tails and it's louder than that 馃
 

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I don't want to sound cookie-cutter here, but back in the day, I rather liked the sound of Flowmasters. And I think it all depends on the vehicle, the engine, and the exit location.

I knew a guy with two-chamber on a Camaro and it was way too loud, as you mention. However, a two-chamber on my V6 Regal sounded quite nice, was like a V8 at idle. I've since driven a V8 Cutlass with a three-chamber and it has a nice growl without being obnoxious.
 

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Discussion Starter · #4 · (Edited)
This is what it sounded like before with the cast manifolds and "quiet" mufflers...lol...

Once the snow melts and driveway dries out, the glasspacks are going on....

 

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Discussion Starter · #5 · (Edited)
When I bought these, I looked through them thinking they were just glasspacks with turn downs but you can't see light through them and looking through the inlet end, you can see a baffle block off plate. I wonder if I were to drill a bunch of holes or just one big hole in the baffle if it would give me the sound I want. I can't return them so why not modify them to my liking?

Or use the glasspacks and sell these...
 
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I thought your videos sounded fantastic, but if your going for loud and you can get a drill bit in there...start small (like 3/8") and work up to the sound your after. Those uni-bits with a long extension should make easy work of it given a straight shot! It does not take much of a hole to let sound out. I never cared for the way glasspacks sounded once they started cackling...sometimes on the way up and mostly when the throttle was let off of. WAAAAA- BA AB BA BA BA BA...But, I'm getting older and losing my hearing AND have always been a fan of the turbo mufflers on these old cars. I get more of kick out of a Quarda-Jet opening up...WAAA - WAAAAAAAAA! lol
 

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Discussion Starter · #7 ·
I thought your videos sounded fantastic, but if your going for loud and you can get a drill bit in there...start small (like 3/8") and work up to the sound your after. Those uni-bits with a long extension should make easy work of it given a straight shot! It does not take much of a hole to let sound out. I never cared for the way glasspacks sounded once they started cackling...sometimes on the way up and mostly when the throttle was let off of. WAAAAA- BA AB BA BA BA BA...But, I'm getting older and losing my hearing AND have always been a fan of the turbo mufflers on these old cars. I get more of kick out of a Quarda-Jet opening up...WAAA - WAAAAAAAAA! lol

Yeah, for some reason it sounds way better in my video than in real life. If it sounded that good in real life, I would be happy...lol... I'm going to run them for a bit and see if they get any louder once the packing compresses some. A friend said to fill them with water and run them wet to compress the packing to make them louder. I've never heard of this trick before but I'll try it. I mean, what's the worse that can happen? They get quieter?
 

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What about the Pypes M80 ? Or go from the headers to an x pipe then dump before the axle or out to the side so fumes don't get into the cockpit... with no mufflers.
 

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Dumping to the side right in front of the rear tire adds 20% sound to the driver in my opinion with the same muffler/exhaust setup (maybe 30%). No mufflers, well that's some serious sound/noise! If electric cutouts were more reliable, I'd have them on all my vehicles. I do miss the days during the builds that there was no mufflers on the project. Not enough to go without, but I do miss making the noise.
 

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Dumping to the side right in front of the rear tire adds 20% sound to the driver in my opinion with the same muffler/exhaust setup (maybe 30%). No mufflers, well that's some serious sound/noise! If electric cutouts were more reliable, I'd have them on all my vehicles. I do miss the days during the builds that there was no mufflers on the project. Not enough to go without, but I do miss making the noise.
But doesn't an x pipe make it quieter and maybe go with tail pipes and no mufflers if you're looking for louder idk, do you have a video of the open headers? Also turn downs by the axel is going to kick up all kinds of dust right? I have Doug's exhaust cutouts coming on the 19th hopefully from Jegs so we'll see how that goes.
 

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I know space is limited underneath these cars, and some purists would probably have my head for mentioning this, but the 80s/90s Fox-body Mustangs had a nice H-pipe setup available that gave a nice sound. Never heard of one on these (probably for a reason), but I wonder if such a setup is even possible, and if so, what it would sound like?
 

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But doesn't an x pipe make it quieter and maybe go with tail pipes and no mufflers if you're looking for louder idk, do you have a video of the open headers? Also turn downs by the axel is going to kick up all kinds of dust right? I have Doug's exhaust cutouts coming on the 19th hopefully from Jegs so we'll see how that goes.
Here's my somewhat inexperienced theory on exhaust, X or H pipes, and where the exhaust exits the car....

Given the firing order of a V8 Pontiac (other makes of V8 engines are similar in that they do not fire equally from side to side)...

Circle Font Auto part Illustration Pattern


You can see that the left bank fires #1, then it jumps to the right bank for #8 then #4 on the same right side, then back to the left for #3, then back to the right bank for #6, then back to the left for #5 & 7, then back to the right for the last in the sequence...#2, then it starts over. This gives a straight dual exhaust (no cross pipe) a syncopated rhythm for each of the lone tailpipes. For example, the left bank goes...Whopp - void - void - whopp - void - whopp - whopp - void. The opposite for the right bank. With straight duals out the back of the car, you get a pretty consistent sound because all the noise is blending together since it is all coming out near the same place. Switch that to each pipe exiting on opposite sides of the car and the syncopated sound it magnified because you don't get much of the opposite side's sound mixing with the side you are on...now you get the Harley effect or a big cam sound. I really like this effect, but don't like the fact that it is louder in the cab for the driver.

Now, add a cross pipe...the syncopated rhythms get mixed in the exhaust which dulls the fake big cam sound. This may make it sound quieter, but my thoughts are that it makes it sound smoother and less whoppy. It may have some sound deadening due to the extra pipe works, but I'd bet it's mostly the affect of equalizing the sound between the two pipes.

I've never had a cross pipe on any of my cars, but it's my understanding the the cross pipe helps equalize the pressure/vacuum surges from the syncopated nature of the firing order and which side the firing order commands. This helps each pipe to have a more constant flow throughout the length of the exhaust. You still have the rhythm of all 8 cylinders, but the voids in the left bank have been mostly filled with the whopps of the right bank and visa-versa. You can imagine what is happening on just one of the banks past the exhaust manifold or header with a straight pipe...#1 fires and the exhaust valve closes...now that pulse is waiting for #3 to happen to help it along. With the cross pipe...the waiting is reduced due to the help of the opposite bank.

In my opinion, the H Pipe is just a more affordable version of the X pipe (and takes less space). The H pipe would yield more sound deadening, however little, due to the fact that it redirects the sound (and exhaust flow) at a 90掳 angle where the X pipe lends itself to a much less change of exhaust and sound flow direction. That 90掳 angle jams the sound harshly into the connecting pipe that will absorb the sound more so than if it was just shooting down a straight (or slightly bent) pipe.

That's enough of my theories, but I have to say that getting the exhaust to exit past the edge of a passenger vehicle is very important due to the fumes. We all know this, but in my youth I didn't realize how important that was. Some fume exposure to a young person is nothing compared to the same exposure as you get older...and as mentioned, there's a fair amount of road dust that gets kicked up by down turns which will stick to the underside and tail. That's not a big deal if you don't mind the extra clean-up come wash time.

Don't take my ramblings as hard facts (except the fume comments). I'd like to hear thoughts from those with more time experimenting with exhaust combinations.

Now, I have to get to polishing some stainless trim for my '67!
 

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OP, you might also consider this. I believe Summit or some other mail-order performance place sold some type of diffuser-based muffler system that basically was infinitely customizable by mixing and matching different diffuser discs to alter the sound / backpressure, etc., which could get interesting with the Pontiac-specific info mentioned above.

Also, OP, the previous poster mentioned a very good point -- getting the exhaust to exit past the edge of the vehicle being important. This is not only to reduce noise level, but also to prevent carbon monoxide poisoning. While exiting forward of the drive tires looks and sounds cool, this puts your exhaust fumes within striking distance, especially in traffic, in addition to the point of kicking up dust.
 
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Here's my somewhat inexperienced theory on exhaust, X or H pipes, and where the exhaust exits the car....

Given the firing order of a V8 Pontiac (other makes of V8 engines are similar in that they do not fire equally from side to side)...

View attachment 149505

You can see that the left bank fires #1, then it jumps to the right bank for #8 then #4 on the same right side, then back to the left for #3, then back to the right bank for #6, then back to the left for #5 & 7, then back to the right for the last in the sequence...#2, then it starts over. This gives a straight dual exhaust (no cross pipe) a syncopated rhythm for each of the lone tailpipes. For example, the left bank goes...Whopp - void - void - whopp - void - whopp - whopp - void. The opposite for the right bank. With straight duals out the back of the car, you get a pretty consistent sound because all the noise is blending together since it is all coming out near the same place. Switch that to each pipe exiting on opposite sides of the car and the syncopated sound it magnified because you don't get much of the opposite side's sound mixing with the side you are on...now you get the Harley effect or a big cam sound. I really like this effect, but don't like the fact that it is louder in the cab for the driver.

Now, add a cross pipe...the syncopated rhythms get mixed in the exhaust which dulls the fake big cam sound. This may make it sound quieter, but my thoughts are that it makes it sound smoother and less whoppy. It may have some sound deadening due to the extra pipe works, but I'd bet it's mostly the affect of equalizing the sound between the two pipes.

I've never had a cross pipe on any of my cars, but it's my understanding the the cross pipe helps equalize the pressure/vacuum surges from the syncopated nature of the firing order and which side the firing order commands. This helps each pipe to have a more constant flow throughout the length of the exhaust. You still have the rhythm of all 8 cylinders, but the voids in the left bank have been mostly filled with the whopps of the right bank and visa-versa. You can imagine what is happening on just one of the banks past the exhaust manifold or header with a straight pipe...#1 fires and the exhaust valve closes...now that pulse is waiting for #3 to happen to help it along. With the cross pipe...the waiting is reduced due to the help of the opposite bank.

In my opinion, the H Pipe is just a more affordable version of the X pipe (and takes less space). The H pipe would yield more sound deadening, however little, due to the fact that it redirects the sound (and exhaust flow) at a 90掳 angle where the X pipe lends itself to a much less change of exhaust and sound flow direction. That 90掳 angle jams the sound harshly into the connecting pipe that will absorb the sound more so than if it was just shooting down a straight (or slightly bent) pipe.

That's enough of my theories, but I have to say that getting the exhaust to exit past the edge of a passenger vehicle is very important due to the fumes. We all know this, but in my youth I didn't realize how important that was. Some fume exposure to a young person is nothing compared to the same exposure as you get older...and as mentioned, there's a fair amount of road dust that gets kicked up by down turns which will stick to the underside and tail. That's not a big deal if you don't mind the extra clean-up come wash time.

Don't take my ramblings as hard facts (except the fume comments). I'd like to hear thoughts from those with more time experimenting with exhaust combinations.

Now, I have to get to polishing some stainless trim for my '67!
Here's my somewhat inexperienced theory on exhaust, X or H pipes, and where the exhaust exits the car....

Given the firing order of a V8 Pontiac (other makes of V8 engines are similar in that they do not fire equally from side to side)...

View attachment 149505

You can see that the left bank fires #1, then it jumps to the right bank for #8 then #4 on the same right side, then back to the left for #3, then back to the right bank for #6, then back to the left for #5 & 7, then back to the right for the last in the sequence...#2, then it starts over. This gives a straight dual exhaust (no cross pipe) a syncopated rhythm for each of the lone tailpipes. For example, the left bank goes...Whopp - void - void - whopp - void - whopp - whopp - void. The opposite for the right bank. With straight duals out the back of the car, you get a pretty consistent sound because all the noise is blending together since it is all coming out near the same place. Switch that to each pipe exiting on opposite sides of the car and the syncopated sound it magnified because you don't get much of the opposite side's sound mixing with the side you are on...now you get the Harley effect or a big cam sound. I really like this effect, but don't like the fact that it is louder in the cab for the driver.

Now, add a cross pipe...the syncopated rhythms get mixed in the exhaust which dulls the fake big cam sound. This may make it sound quieter, but my thoughts are that it makes it sound smoother and less whoppy. It may have some sound deadening due to the extra pipe works, but I'd bet it's mostly the affect of equalizing the sound between the two pipes.

I've never had a cross pipe on any of my cars, but it's my understanding the the cross pipe helps equalize the pressure/vacuum surges from the syncopated nature of the firing order and which side the firing order commands. This helps each pipe to have a more constant flow throughout the length of the exhaust. You still have the rhythm of all 8 cylinders, but the voids in the left bank have been mostly filled with the whopps of the right bank and visa-versa. You can imagine what is happening on just one of the banks past the exhaust manifold or header with a straight pipe...#1 fires and the exhaust valve closes...now that pulse is waiting for #3 to happen to help it along. With the cross pipe...the waiting is reduced due to the help of the opposite bank.

In my opinion, the H Pipe is just a more affordable version of the X pipe (and takes less space). The H pipe would yield more sound deadening, however little, due to the fact that it redirects the sound (and exhaust flow) at a 90掳 angle where the X pipe lends itself to a much less change of exhaust and sound flow direction. That 90掳 angle jams the sound harshly into the connecting pipe that will absorb the sound more so than if it was just shooting down a straight (or slightly bent) pipe.

That's enough of my theories, but I have to say that getting the exhaust to exit past the edge of a passenger vehicle is very important due to the fumes. We all know this, but in my youth I didn't realize how important that was. Some fume exposure to a young person is nothing compared to the same exposure as you get older...and as mentioned, there's a fair amount of road dust that gets kicked up by down turns which will stick to the underside and tail. That's not a big deal if you don't mind the extra clean-up come wash time.

Don't take my ramblings as hard facts (except the fume comments). I'd like to hear thoughts from those with more time experimenting with exhaust combinations.

Now, I have to get to polishing some stainless trim for my '67!
So I was just thinking of ways to make it louder because isn't that what you want ? It was too loud with the open headers and now too quiet with mufflers on the collectors so I was thinking full exhaust w/tails to get the fumes away but maybe that would be too loud so like you said the x pipe would quiet it down some right? Just throwing ideas out there with not having tried it, I like my sound but wouldn't mind it a little louder without rapping or droning so I hope the cutouts do that without being annoyingly loud that's why I'm thinking of putting them right before the mufflers and putting a tail piece on I have leftover to exit to the side in front of the rear tires so fumes don't get under the car, so we'll see?
 

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I think your cut-outs with side exit pipes is going to be too cool, Baaad! And, I think your right about adding an H pipe AND pipes all the way out the back quieting it down compared to the same set up without mufflers. It would not quiet it down enough for me, but maybe just right for Boomstick...Probably not quiet enough for the authorities however! lol The glasspacks may have to go in as well, but htat's up to Boom's preference. I find myself picky about some things more than others...it's the exhaust and stance that usually requires several attempts to get it "just right".
 

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snip It would not quiet it down enough for me, but maybe just right for Boomstick...Probably not quiet enough for the authorities however! lol *
Tire Car Vehicle Automotive lighting Wheel
 
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Font Circle Auto part Illustration Pattern


"Note: the 307 Pontiac V8 engine rotates clockwise".
PONTIAC 307? 馃 I've never heard of such a beast.


I knew Chevrolet built a 307 to replace the 283, which lasted all of about five years. Olds built a 307 later as well, but I've never heard of a Pontiac 307? Chevy or Olds engine in a badge-engineered Pontiac offering perhaps?
 

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I think it was an Olds engine that was used in the Pontiacs and according to the web...it was the last carbureted engine GM ever manufactured. It was used in the early to mid 80's Bonneville's and Parisienne's. I just borrowed that photo clip from the web because it had the firing order and the cylinder assignments for my example.
 

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Wheel Tire Car Vehicle Hood
Angled toward rear helps get the fumes away from cabin. She is not to as loud as before the headers were installed. Will learn to post videos here and put one up.
 

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View attachment 150005 Angled toward rear helps get the fumes away from cabin. She is not to as loud as before the headers were installed. Will learn to post videos here and put one up.
What kind of mufflers if any ? I'm thinking of doing that when I install my cutouts but don't know if I want them sticking that far out, any problems with clearance or banging off the frame?
 
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