Dual Exhaust on a 4.9 Sixty Special

[nsharma1999]

I'm just wondering if anyone has installed dual exhaust on a 1992 4.9 Sixty Special, Fleetwood or Deville. I want to keep my car stock but thought I would replace the stock exhaust with duals cause I think it would look so good and maybe get me a little better performance and gas mileage. Anyone out there do this? Your thoughts, comments.

[bandit600]

I have done just that on my '92 Fleetwood Sixty Special. Camaro exhaust from MagnaFlow and slash cut chrome tips. It looks awesome, and the sound is great. A low rumble at idle, not loud. A slight drone while accelerating, but not to the point that it's anoying. you get used to it, i love it.


Camaro exhaust is in & out on one side and out on the other side. You'll have to measure the diameter of the stock exhaust pipe. Just cut the old exhaust off right at the muffler and have the new one welded on. Then attach to the stock hangers (might need new rubbers and hangers, but the placement is spot on).

With a free flowing air filter, i noticed better mileage and maybe slightly more pep, but that could be suggestive without testing on a dyno.

Definitely worth it just for the look and sound.

Will try to get pictures for you.

[Rodya234]

It would be very difficult to install true duals on a C-body Cadillac. But, if you want that dual exhaust look, the best thing to do would either get a dual out muffler or install a T-pipe on the current one. My car has a Edelbrock SDT dual out with a tip from another '92 Deville and it looks pretty cool.

Performance wise, the extra pipe will do virtually nothing because it's so short. However, your power increase will come in if you decide to install a higher flow muffler or cat.

[dirt_cheap_fleetwood]

Go and find the muffler from a 3rd/4th gen Camaro/Firebird and put it in there. They sit sideways and are single in/dual out designs that sound great and will boost your performance a little. I am thinking about doing it to my Fleetwood this spring.

Rodya, do you know of any other single in/dual out designs that would work (the kind where the tailpipes are opposite each other, not right next to each other like yours)? I am looking for one that is quiet at idle and at high rpm but makes my car have just a little (very little) growl/throaty sound. I live in a quiet neighborhood and I would feel horrible if I wake up the neighbors when I come home from work late at night.

[bandit600]

The Camaro exhaust fits perfectly. Attached are pictures installed on my car. Please excuse the dirt and snow. It looks much better when the tips are clean and polished.

As for sound, it won't wake any neighbors. But you will hear a nice low growling/rumble when you get close, especially at idle.

Obviously its not a true dual exhaust system, but it does the trick.

[Rodya234]

Heres a link for the magnaflow from a Camaro/Firebird V6.
http://www.magnaflow.com/02product/s...e=main&id=7716

I'll probably edit this post as I find more, but I'm at school right now and my ability to search this stuff is kind of limited.

The side-by-side out is a little harder to deal with because I had to install a 180 degree transition pipe and then another 90 in order to make it fit. And as you guys well know there isn't alot of space back there. I also found out the hard way that it's very difficult to weld stainless-steel.) I'll be getting two polished stainless turn-down tips so I can have them shiney but still keep the "OEM" look.

The only advantage was that the Edelbrock was only $115 bucks.

[dirt_cheap_fleetwood]

Thanks Bandit, that's just what I wanted to know. What is the exact muffler you have on yours? Is it a Magnaflow/Flowmaster replacement or is it just one you ripped off a junked out Camaro? Also, did you have to custom make the tailpipe for the left side or did you find one that fits nicely?

[bandit600]

Brand new Magnaflow. Not sure of the pipe diameter though, you would have to measure on the Caddy then look it up in the Magnaflow catalog to make sure you get the right one.

According to Walker, the mid-pipe diam right before the exhaust is 2.5". Best fit Magnaflow exhaust would be part# 12265 (2.5" out) or 12266 (2.25" out). again, best to measure first.

The tailpipes that come out on each end are just 90* elbows the muffler shop bent on site to get the angles right, then welded the polished tips on the ends.

If you do it yourself, it should be easy enough with store bought elbows. the tricky part is getting the angles right on the tailpipes and tips once the muffler is installed. Definitely a 2 man job. 1 to measure, hold the pies and weld, and another to stand about 5 feet back right before tacking the joints to eyeball if everything looks symmetrical.

[nsharma1999]

Thank you guys. Thats was highly appreciated. I think I'll be going for the MagnaFlow Camaro Firebird muffler and custom bend the tailpipes. Then I put some simple chrome downturns... don't want to deviate too far from stock.

Also, the pics were worth a thousand words. If anyone else has any pics of their Fleetwood or Sixty with this I would love to see them.

Nick

[dirt_cheap_fleetwood]

^ None of the exhaust on my car is welded. I just redid it from the cat back last winter and it is all held by clamps. It won't sound as great as a fully welded exhaust but it will do the trick.

[Rodya234]

I just found out that Edelbrock makes an SDT now that has opposite side outs. Can you guess what I want for Christmas now?

[Rodya234]

For future reference, if you don't want to have a high volume muffler to get dual exhaust, walker makes a QuietFlow 3 with the same split out design.

[dirt_cheap_fleetwood]

^ I couldn't find the Walker dual out design you mentioned. Do you have a direct link?

[Rodya234]

well, its not direct, but this is the link to their catalog: http://www.walkerexhaust.com/catalog...letypescrn.asp

look up 2002 Camaro or Firebird and the diagram of the exhaust will have the muffler part number.

It's hard to get a direct link because their website is in ASP and the link doesn't vary as the page changes.