# exhaust system for a 66



## sixtysix (Jul 2, 2010)

I am working on a 66 project car. I see that I have many options for an exhaust. What is the benefit of an x pipe over stock dual exhaust? I am considering a flow master exhaust system, or is an exhaust from a muffler shop equal?

sixtysix


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## BearGFR (Aug 25, 2008)

X-pipes are good because they let each side of the engine "see" the exhaust flow from the other side, and that flow can help keep things moving along. It's called scavenging, where the exhaust flow from one side helps to keep the gasses moving on the other side, or to start them moving if they aren't already. Without something like this, once the flow stops the only way to get it going again is for the pistons on that side of the motor to "push" on it to get it moving, and that takes energy out of the system that could have otherwise gone out through the crank shaft in the form of torque.

I'd recommend that you look at "all" the vendors, listen to sample videos to find the sound you like. Flowmasters have a reputation for an annoying "droning" at cruise rpm, but some folks like that.

Unless you know for certain you're making more that 550 HP, don't put on anything bigger than 2 1/2" pipes, front to back. Otherwise you'll lose some low end torque.

Bear


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## freethinker (Nov 14, 2009)

sixtysix said:


> I am working on a 66 project car. I see that I have many options for an exhaust. What is the benefit of an x pipe over stock dual exhaust? I am considering a flow master exhaust system, or is an exhaust from a muffler shop equal?
> 
> sixtysix


its more hype than any thing else.


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## geeteeohguy (Feb 2, 2008)

Bear said it like it is. Original GTO's don't run an X or H pipe, but have different mufflers and sometimes resonators. X or H pipes do help scavenging, as stated above. They are a PITA when doing clutch jobs, head work, etc. as they are more "in the way" and make dropping the exhaust more labor intensive. I run stock exhaust on the '67 and Hedman Hedders with Walker Turbo mufflers in the '65, and get no droning. I am not a fan of Flowmasters. Too loud, too much resonance, and that gets tiresome if you drive the car more than 10 miles at a time. If I were to re-do the exhaust on either car, I would consider an X or H pipe, though.


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## daveh70 (Sep 4, 2008)

You can also consider the Gardner Exhaust System, if you go the original route. Sounds like you may not be looking for that though...

Exhaust Systems - Gardner Exhaust Systems - Muscle Car Exhaust Sytems by Gardner

Dave


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## BearGFR (Aug 25, 2008)

geeteeohguy said:


> They are a PITA when doing clutch jobs, head work, etc. as they are more "in the way" and make dropping the exhaust more labor intensive.


True that. Just the other day I dropped the section between the headers and the mufflers and welded all the joints to get rid of the clamps. I still have clamps at the header reducers and at the muffler inlets, so in theory I'll be able to just drop that section out whenever I need access ..... in theory.

Here's what it looked like, front to back, before...









Bear


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## 66tempestGT (Nov 28, 2009)

i have a friend with a muffler shop that does great work. he installs custom systems for what i would pay just to buy a nice kit and his stuff is all welded together instead of clamps. plus i dont even get my hands dirty. there are some butchers out there but if you can find a reputable guy i dont know why mail order kits could be any better.


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## 66tempestGT (Nov 28, 2009)

i used to run a center section with flanges on both ends so that i could pull it out to run open exhaust. going with electric cutouts this time.


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