Dual Exhaust
Thread Starter
8th Gear
Joined: Sep 2007
Posts: 8
Likes: 0
From: Butler PA
Dual Exhaust
I have an 80' and I want to upgrade to a true dual exhaust from my stock system and I was wondering if a system from a 74' would work or if I would be better off getting custom pipes bent.
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Dual Upgrade
You first need to look at local laws.
I went to one of our vendors and got one of these for my 78.
http://www.corvettecentralexhaust.com/c3perfdual.htm
With that and recurve on the distributor the car has power and smooth on acceleration. Its that simple.
I went to one of our vendors and got one of these for my 78.
http://www.corvettecentralexhaust.com/c3perfdual.htm
With that and recurve on the distributor the car has power and smooth on acceleration. Its that simple.
Burning Brakes
Joined: Oct 2006
Posts: 1,006
Likes: 28
From: Lutz Florida
I'm not sure about an 80. Does the crossmember have the holes for duals? My 76 did and the dual system from Corvette Central bolted right up to the stock exhaust manifolds with no problem. If in doubt give them a call.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
Your profile isn't filled out so we don't know where you live. As mikep3 said, you need to check you local laws to verify a true dual is OK. IF the laws where you live allow, I highly recommend full length ceramic coated headers and a custom bent true dual exhaust. A number of CF members (including me) had major fit problems with a prebent system. I gave up and went with a custom bend system with a cross-over pipe. PERFECT! 
Thread Starter
8th Gear
Joined: Sep 2007
Posts: 8
Likes: 0
From: Butler PA
I'm in PA and I know my local laws allow for true duals as long as I have an antique plate on it. I just know for sure that I can get a true dual system for a 74' but it doesn't say anything about an 80' obviously for legal reasons. I just have the fake duals now.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
That would cost you less at a muffler shop, than duals thru any vendor.
Thread Starter
8th Gear
Joined: Sep 2007
Posts: 8
Likes: 0
From: Butler PA
Ya there is local muffler shops around but I don't know if they have machine to do mandrel bends or not. I would think so, but also I don't know if they have the high quality stainless steel. I'm planning on looking more into it but I was just inquiring about what you guys think. Thanks for the suggestions!
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Dual Upgrade
I looked at the link,
http://www.corvettecentralexhaust.com/c3perfdual.htm
The later years 79 to 82 have the both pipes going down one side. My 78 has two holes in the cross member and was supplied with just four pipes, two from the engine to cross member and two from cross member to the stock mufflers.
http://www.corvettecentralexhaust.com/c3perfdual.htm
The later years 79 to 82 have the both pipes going down one side. My 78 has two holes in the cross member and was supplied with just four pipes, two from the engine to cross member and two from cross member to the stock mufflers.
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Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
A simple modification to your cross member will give you the ground clearance you need on the left side. That was one of the best mods I made to my '80. I can tell you exactly how to modify the cross member to route the left pipe similar to the right pipe in the stock location. Check my other posts for more info, or PM me with your e-mail address so I can send you a link to more pics of my exhaust with full length ceramic coated Dynomax headers and custom 2 1/2" pipes to Flo-Pro baffled mufflers. I have a video with sound so you can here this setup too.
Le Mans Master
Joined: Jan 2006
Posts: 5,921
Likes: 0
From: GA "When I grow up, I'm gonna get a Trans Am and run from the cops". Direct quote from my 4yo son.
Your profile isn't filled out so we don't know where you live. As mikep3 said, you need to check you local laws to verify a true dual is OK. IF the laws where you live allow, I highly recommend full length ceramic coated headers and a custom bent true dual exhaust. A number of CF members (including me) had major fit problems with a prebent system. I gave up and went with a custom bend system with a cross-over pipe. PERFECT!
Race Director
Joined: Oct 2000
Posts: 11,891
Likes: 3
From: Kansas City, MO ...I'd like to go fishing and catch a fishstick. That'd be convenient. - Mitch Hedberg
Actually, per federal law, you can never run a dual exhaust. Your car came with one catalytic converter and that is the only LEGAL setup you can use.
However, that doesn't stop very many people. I'm considering this kit http://www.mamotorworks.com/corvette-4-36-1303.html I am also considering adding a single 3" cat in the appropriate location with a set of 2-2.5" to 3" Y's to make it work.
However, that doesn't stop very many people. I'm considering this kit http://www.mamotorworks.com/corvette-4-36-1303.html I am also considering adding a single 3" cat in the appropriate location with a set of 2-2.5" to 3" Y's to make it work.
Racer
Joined: Oct 2006
Posts: 396
Likes: 3
From: Buffalo New York
Actually, per federal law, you can never run a dual exhaust. Your car came with one catalytic converter and that is the only LEGAL setup you can use.
However, that doesn't stop very many people. I'm considering this kit http://www.mamotorworks.com/corvette-4-36-1303.html I am also considering adding a single 3" cat in the appropriate location with a set of 2-2.5" to 3" Y's to make it work.
However, that doesn't stop very many people. I'm considering this kit http://www.mamotorworks.com/corvette-4-36-1303.html I am also considering adding a single 3" cat in the appropriate location with a set of 2-2.5" to 3" Y's to make it work.
Thread Starter
8th Gear
Joined: Sep 2007
Posts: 8
Likes: 0
From: Butler PA
Ya in PA it is legal for a car 20 or 25 years old, I'm not sure, to have true duals but you have to pay for a antique license plate and there are restrictions as to when you can drive and how far you can drive a year, but it also makes the insurance quite a bit cheaper. Thanks for all the help. I know for sure I want to get headers, I just have to talk to the guys at the local muffler shop to see what it would cost there. Thanks again!
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
The block huggers were bad news. They fried 4 sets of spark plug wires, they melted the poly pads in both motor mounts, and I had to remove the headers to change the spark plugs. Nuf said?
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Thanks for the head up
Well, I guess that we need to clean and paint the cast iron ram horns on my vortec head change.
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
In comparison, the Dynomax full length ceramic headers I switched to are swept back from center. They also come farther out from the exhaust ports before going down giving better room for spark plug access. I saw some shorty headers that were swept back and had good plug access too. Hugging the block is not a priority for some headers.
Race Director
Joined: Oct 2000
Posts: 11,891
Likes: 3
From: Kansas City, MO ...I'd like to go fishing and catch a fishstick. That'd be convenient. - Mitch Hedberg
I tried to PM you, but your inbox is full. Is that the exhaust that I'm asking about in this thread http://forums.corvetteforum.com/show....php?t=1928426 ?
Le Mans Master
Joined: Mar 2004
Posts: 7,499
Likes: 1,507
From: Little Rock AR
AK Mal,
Yes that is the MAD True Duals setup with (2) Dynomax C3 Vette muffs. It took a bit of work to get it to fit and I had to MIG it together as it is very thick. I would probably buy one again if I ever needed one.
I also added a crossover to that system later where the 2 pipes run close together. The sound chage when I added the crossover was not much with this combination. The performance change from adding the crossover was also minimal with this particular setup running the stock 350/350 cam.
I have had more substantial results when adding crossovers on combinations where the exhaust system was more taxed. I expect that was due to the narrower lobe centers/duration issues with the other engine. The setup that did show an improvement also had long tube headers and performance muffs. The crossover effects were more pronounced with that setup. Your results may vary.
I saw where you were trying to run dual cats. I would not do that personaly. I might be more inclined to run stock pipes with a single high flow cat if you will need to have the emissions equipment. I know that will fit and work well for you.
-Mark.
Yes that is the MAD True Duals setup with (2) Dynomax C3 Vette muffs. It took a bit of work to get it to fit and I had to MIG it together as it is very thick. I would probably buy one again if I ever needed one.
I also added a crossover to that system later where the 2 pipes run close together. The sound chage when I added the crossover was not much with this combination. The performance change from adding the crossover was also minimal with this particular setup running the stock 350/350 cam.
I have had more substantial results when adding crossovers on combinations where the exhaust system was more taxed. I expect that was due to the narrower lobe centers/duration issues with the other engine. The setup that did show an improvement also had long tube headers and performance muffs. The crossover effects were more pronounced with that setup. Your results may vary.
I saw where you were trying to run dual cats. I would not do that personaly. I might be more inclined to run stock pipes with a single high flow cat if you will need to have the emissions equipment. I know that will fit and work well for you.
-Mark.