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Discussion Starter #1
Hi All,

Looking for some recommendations on an exhaust system for my 1968 Impala WAGON. I'm converting from a 307/Powerglide to a 427BB/-5-spd stick combination and will require a new dual exhaust. I'm open to stainless or aluminized, but would prefer at least 2.5" dia. pipe. I plan to run headers at this point, and have the ability to modify the front pipes to fit if there is a good "stock" system out there. Appreciate all input, particularly if you have personal experience, and ESPECIALLY if you have a wagon, which are unique in regards to the exhaust. Thank you in advance!

-Ben
 

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I would suggest a 496 instead of a 427. A 496 looks like a 427 so a 427 390 horse decal looks like it belongs there. You do this because of today's gas. A BBC is a high performance engine by design and doesn't like to burn low octane gas. It is very inefficient and a high polluter which is why it was dropped from production and banned from California by 1969. By increasing displacement you can make nearly as much power as a big small block (a 400 cube SBC bored thirty over will make 500 horse with the right heads and cam). This is why the ZZ502 makes the same 500 horsepower as the smaller 406. But either engine (427 or 496 will produce far more engine torque than the five speed Borg-Warner T-5 can handle. So I hope your five speed is a Tremec or a Doug-Nash, or a Borg-Warner T-56 and not the one designed to be put in a four cylinder Pinto in 1982.

I used stainless steel factory manifolds off of a 454 powered motor home with two and a half inch exhaust pipes and dual exhaust and they worked out just fine. They are made of two inch stainless tubular steel pipe welded into a log style exhaust manifold with the exits in the stock location; same as the cast iron big block manifolds.

Big Dave
 

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Big Dave,

I appreciate your input, and don't disagree on the 496/502 being a better street engine. Unfortunately (and fortunately), the 427 came out of my father's car, and is fresh, fully complete, and ready to install. Planning to use the new TKX-600, so good there. I'm specifically looking for recommendations on an existing exhaust system kit from X-company, which someone has had a good experience with. Thanks!

-Ben
 

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The only commercially available option I've tried in mine is the Magnaflow exhaust. It didn't fit well and had to be cut up and adjusted all over the place. Tried 3 different sets of headers before I settled with Sanderson BB-10. They were perfect. Hookers had not enough ground clearance. Headmans had to be beat to hell to fit around the steering box. I lived with the Magnaflow exhaust for a couple of years but now I'm just building a custom one from 304. If you can weld it's about the same price as a prefab and will actually fit.
Last item that will impact you is engine frame stands and motor mounts. I have the correct BBC frame stands but used SBC motor mounts the first time, which leaves the engine sitting ~ 3/4" lower and also causes clearance issues. Correct frame stands are out there but hard to find. Lots of staring through old parts catalogs tells me the aren't the same as the SBC versions.
 

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Discussion Starter #5
John,

I appreciate the post. That's exactly the type of information I'm looking for. The Magnaflow was the one system I was seriously looking at, so good to know your thoughts on it. I guess I'll be avoiding that one now. I already have a set of Hooker headers from my dad's car, and I've always thought they fit quite well, but he does have manual steering, and I have power steering. I'll definitely take a look at the Sanderson's as well. Thanks again.

-Ben
 

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The Hooker long tube headers fit through the chassis with no issues. I have 2" drop spindles and it put the collectors ~ 4" off the ground. There should be some pictures of the header clearance I have now near the end of my build thread. Nothing but space with the Sanderson headers.
 

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Discussion Starter #8
Thanks John. I look forward to looking through your build thread. My dad's car is a '69 Belair that he purchased new, so yours is near to my heart.
 

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I would suggest a 496 instead of a 427. A 496 looks like a 427 so a 427 390 horse decal looks like it belongs there. It is very inefficient and a high polluter which is why it was dropped from production and banned from California by 1969. By increasing displacement you can make nearly as much power as a big small block (a 400 cube SBC bored thirty over will make 500 horse with the right heads and cam).


Big Dave
Dave, please realize that not everyone needs to be convinced to upgrade to a huge cube big block. Some people actually like small cube big blocks (396, 427), some people can't afford to build anything other than a stock small inch big block, some people have no desire to build a tire shredding engine, some people maybe still think a little bit in terms of fuel economy, some people want numbers matching engines in their cars and the list of reasons goes on and on. We don't all think the same about our old cars and that is a good thing. Personally I love nothing better than a 427 and a Muncie 4 speed but not everybody thinks the same way, and I'm glad.
 

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There's nothing like keeping your all original 396 car, 396 as well as the 427 car, 427.
 

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I have a 67 big block wagon. Bought the head pipes and tailpipes from Waldron Exhaust in Michigan. Factory tailpipes are 2" while the head pipes are 2 1/2. They'll let you upsize the tailpipes which is what I did. I went to 2 1/4". I think the largest they'll do is 2 1/2" but when you upsize, they won't warranty the fit. Mine fit fine so don't hesitate buying a system from these guys. They do nice work at a fair price.
 

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Discussion Starter #14
Sandrone21,

Thanks for the reply. Nice looking car. Good to hear another opinion about the Magnaflow system. Did the system fit without any mods or issues? What headers and mufflers are you running? Any video of the sound?

-Ben
 

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Discussion Starter #15
I went on 367's recommendation and called Waldron Exhaust. They seems to have a nice complete factory system, and will upgrade the tailpipes to 2.25" if desired, but not 2.50", which is my preference. Nonetheless, they seems to offer a nice system at a fair price, and should fit well being a factory design. They will sell without the mufflers as well, which is nice, as I'm leaning toward something with a straight-thru design for a little extra power. Sincerely appreciate everyone's comments and opinions. Keep 'em coming if you have more thoughts. Happy Friday!
 

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Regardless of whether you have a wagon, 2-dr, or otherwise, I'd love to see some videos of your exhaust to see what they sound like. If you do, please specify exactly what you have including headers vs. exhaust manifold, pipe diameter, specific muffler, etc. Thanks
 

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Sandrone21,

Thanks for the reply. Nice looking car. Good to hear another opinion about the Magnaflow system. Did the system fit without any mods or issues? What headers and mufflers are you running? Any video of the sound?

-Ben
I am running stock headers. I paid a local shop to install the kit and create the transition from the stock headers to the start of the exhaust kit. The shop didn't report any issues. The magnaflow street performance mufflers came with the kit. Don't have any video of the sound, sorry!
 
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