[Joel Koontz]

I got a set of Torque Tech 3" tailpipes and had them installed at a local shop. The tailpipes fit very well. I also had them fabricate a 3" X Style Crossover and pipes between the headers and mufflers. The previous system was a set of 2.5" pipes(no balance tube or crossover) 2.5" Walker Super Turbo Mufflers and Flowmaster Tailpipes. The main reason I changed the exhaust is because I did not like the appearance of the Flowmaster Tailpipes. I don't think I need 3" system(fairly mild 455) but I like the look of 3" tailpipes so I went ahead and got a 3" system. I could not decide what mufflers to use so I had the shop add adaptors to my 2.5" mufflers(I know this is not ideal) and re-used them. I figured I would see how they sound and can change them later if I want.

The car is slightly louder from idle to about 2000 RPM but at higher RPM, 2500+ it is MUCH QUIETER. I am amazed at how much quieter it is. I have a 66 Tri-Power. I could always hear the intake roar to some degree but with the new 3" exhaust it is almost the only thing I hear. I assume that much or all of the Higher RPM noise reduction is due to the X Style Crossover. I have read that they reduce noise but did not realize how much. If you want your exhaust to be quieter I suggest you have an X Style Crossover installed.

I am very happy with the Higher RPM sound(or lack thereof) but would like to reduce some of the resonance at Lower RPM. I was thinking about trying to install some type of "shut off valve" in one of the pipes behind the crossover. This would let me have a Quiet Single Exhaust at low RPM and a full 3" system at Higher RPM. Has anyone ever tried this? Where can I get a 3" valve to install in the exhaust pipe? I have seen "Cutout Valves" in J.C. Whitney. I could modify one of them but they say they fit 1 3/4" to 2 1/4" pipe so I don't think they would work well. It would be great if I could get one that was electric or vacuum operated. I could rig it to the Trans Kickdown Switch or install a Hobbs Vacuum Switch. Either way I could set the valve up so that it would closed under low throttle conditions and open with large throttle openings. Do any cars, trucks or equipment use such a valve? I think it would be cool if I could rig it to work automatically but I will try a cable operated valve if that is all I can find. I have some solenoids, for door locks etc. and I may be able to rig one of them up if I can find a valve.

Thanks, Joel

[Joel Koontz]

I got a set of Torque Tech 3" tailpipes and had them installed at a local shop. The tailpipes fit very well. I also had them fabricate a 3" X Style Crossover and pipes between the headers and mufflers. The previous system was a set of 2.5" pipes(no balance tube or crossover) 2.5" Walker Super Turbo Mufflers and Flowmaster Tailpipes. The main reason I changed the exhaust is because I did not like the appearance of the Flowmaster Tailpipes. I don't think I need 3" system(fairly mild 455) but I like the look of 3" tailpipes so I went ahead and got a 3" system. I could not decide what mufflers to use so I had the shop add adaptors to my 2.5" mufflers(I know this is not ideal) and re-used them. I figured I would see how they sound and can change them later if I want.

The car is slightly louder from idle to about 2000 RPM but at higher RPM, 2500+ it is MUCH QUIETER. I am amazed at how much quieter it is. I have a 66 Tri-Power. I could always hear the intake roar to some degree but with the new 3" exhaust it is almost the only thing I hear. I assume that much or all of the Higher RPM noise reduction is due to the X Style Crossover. I have read that they reduce noise but did not realize how much. If you want your exhaust to be quieter I suggest you have an X Style Crossover installed.

I am very happy with the Higher RPM sound(or lack thereof) but would like to reduce some of the resonance at Lower RPM. I was thinking about trying to install some type of "shut off valve" in one of the pipes behind the crossover. This would let me have a Quiet Single Exhaust at low RPM and a full 3" system at Higher RPM. Has anyone ever tried this? Where can I get a 3" valve to install in the exhaust pipe? I have seen "Cutout Valves" in J.C. Whitney. I could modify one of them but they say they fit 1 3/4" to 2 1/4" pipe so I don't think they would work well. It would be great if I could get one that was electric or vacuum operated. I could rig it to the Trans Kickdown Switch or install a Hobbs Vacuum Switch. Either way I could set the valve up so that it would closed under low throttle conditions and open with large throttle openings. Do any cars, trucks or equipment use such a valve? I think it would be cool if I could rig it to work automatically but I will try a cable operated valve if that is all I can find. I have some solenoids, for door locks etc. and I may be able to rig one of them up if I can find a valve.

Thanks, Joel

[Jim Hand]

Interesting idea of blocking one side of the system, but haven’t tried that. We have found that one of the primary causes of resonance inside the car is very inflexible pipe and muffler hangers. The problem is compounded with any kind of rigid crossover as that ties the two sides together. You may want to look at all the hangers used throughout and see if they allow the pipes to move a little. If very tight or rigid hangers are used, every movement of the engine will be transmitted directly into the body, and you will hear/feel a lot of noise and vibration. Also, assure the tailpipe outlets are outside the body because otherwise, some of the exhaust sounds will be reflected back under and into the body structure.

Joel, for some reason my mail to you bounces. Please send a message so I can see what is wrong with my mail system. Thanks. Jim Hand

[Michael Farich]

Late 70's Chevy 350 4WD pickups and probably other vehicles have a vacuum operated damper between the pass side manifold outlet and exhaust pipe inlet. I think it's 2.25" though.

I found the same low rpm rumble and high rpm quiet effect with the "X" also. My system is only 2.5" all the way back. It rumbles strongly idling around in the parking lot at work but when wound up getting on the interstate the Q-Jet induction roar is much more noticeable even with a closed air cleaner and 4" duct to the grille.
After awhile of daily use any new exhaust will quiet down and lose some of the tinny sound as it gets carboned up on the inside.

[RPM]

One thing I noticed when I installed a X on my 67 GTO is that at cruising speeds (3000+ RPM) I can't hear the exhaust anymore. With seperate duals I always could hear the drone. I am using Walker "Super Turbos" and a full exhaust system.