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Best C3 exhaust system?

V

vettes-xlr8

Guest
I have a '73 350 coupe which I purchased last September. It has low mileage (53k) and is all original. However after ten years of storage I have already replaced the suspension, cooling system, power steering and most of the seals. The exhaust was really quiet despite having holes rusted in both mufflers. When I went to replace the system I wanted something comparable in sound to the Flowmaster system that I had on my C4. Although I was told that it was a cheap "kids" exhaust, I really liked the sound, kind of a low sub-sonic rumble that set off all of the car alarms when I drove through the parking garage at work without being obnoxiously loud.

When I looked around, I found that I didn't have much choice with a C3. Stock, Straight or Chambered. I went for the chambered and boy am I sorry.

Not only is it LOUD, but it backfires like crazy every time I let up on the gas. I'm really attracting a little too much attention to myself with it, especially when I drive down corporate row each morning. :0

Surely someone in here has found what I'm looking for, so please share before I go deaf!

Thanks!!
 

Stingray74CC

Well-known member
Joined
Nov 23, 2001
Messages
183
Location
San Diego, CA
Corvette
Black Cherry 1969 Stingray
I have a 2.5" offroad, underneath Stainless Steel exhaust coming off the stock exhaust manifold and it sounds great. I have the low rumble during idle and acceleration. I don't know what brand name it is, I'll let you know when I find out. Good Luck!
 
7

75SHARK

Guest
I went with headers joining 2.5" pipes for a straight dual exhaust ending up at Dynomax mufflers. I can't tell you how much I luv the sound of these things! They're very civil at idle and crusin around, but when you get-into-it, along comes that great roar 'n rumble tone that speaks like no other! They're probably more on the quiet side when civil, and not as loud as glass-packs or flow masters on the high side. They're somewhat oval shaped, so they fit well, tucking up under the rear valance. Nothing bothers me like seeing a corvette exhaust hanging down, or poor fits! The dynomax tone to me, fits a corvettes persona.
You can test drive some parts before you buy, like I do. I approach people and ask for a ride in their cars. Most comply. Several weeks ago, I was passing thru my old stomping grounds and saw a '67 Chevelle going the other way. His exhaust note behind the 'hairy' cam sounded great! I turned around and followed him into a gas station. Got talking to him about his cool car, and asked for a ride. We drove around for almost an hour, talking tech the whole time. Sure enough, he was running Dynomax's behind his big block. What I was really after was the kind of ride he got off those skinny profile tires. Was a sweet soundin 'jack-hammer' of a ride!
Best of Luck in your choice -Dave
 

Ganey

Well-known member
Joined
Jan 7, 2001
Messages
94
Location
Texas
Corvette
385 CI 77 CORVETTE FE-7 Hi-Perf Sus.
Headers, duals w/ X over pipe & Dynomax or Flowmaster mufflers. Chambered is restrictive. Mufflers should be at the end of system. Adding a crossover pipe will help what you have.
 
H

Hijinx

Guest
I put the smallest mufflers FlowMaster makes at the back of my '73 and it sounds great. I want to put in a crossover, but have not gotten around to it yet. The backfire sounds like another issue, not the pipes. However, I could be wrong. Mine growls nicely around town and is fairly quiet on the highway. In my mind 2.5 inch pipes, with crossovers and small Flowmasters (I think 40 series) is a great setup, whether you use stock manifolds or headers.
 
K

kustomvette

Guest
i have a set of headers on a 350 with 3 inch pipes running all the way back to some raptors. not real loud until you get on it and then it is still not that loud
 

Tom73

Well-known member
Joined
Aug 21, 2001
Messages
1,427
Location
Round Rock, TX
Corvette
73 LS4 Coupe - 04 CE Conv
vettes-xlr8 said:
I went for the chambered and boy am I sorry.

Not only is it LOUD, but it backfires like crazy every time I let up on the gas. I'm really attracting a little too much attention to myself with it, especially when I drive down corporate row each morning.

Surely someone in here has found what I'm looking for, so please share before I go deaf!

I have heard that a crossover pipe will really help to mellow out the chambered exhaust. Also, your carb is probably too rich now since the chambered exhaust has less back pressure. Re-tune the carb and add a crossover and I would bet your problems will be over.

tom...
 

Tom Bryant

Well-known member
Administrator
Joined
Nov 9, 2000
Messages
7,196
Location
Edgerton, Ohio, United States
Corvette
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Pop, bang, pop

That poping and backfiring when you let off of the gas sounds like a bad diverter valve on your A.I.R. pump. That used to be a common problem when these systems were new technology in the '70s. If your cars is so equiped I would have it checked out. It might not have been noticable with the quiet mufflers.

Tom

P.S. Welcome to the Corvette Action Center
 

JCL

Well-known member
Joined
Feb 23, 2001
Messages
56
Location
SEVILLE,OHIO
Corvette
1979 "383" TORCH RED- 2000 Torch Red "FRC."
" Best Exhaust........."

Vettes-xlr8. Another option would be SIDEPIPES. Either the factory look, or one of the aftermarket brands. Great looks, great sound, and great performance. The only draw back, it isn't inexpensive!!! "Sidepipes are the way". JCL
 
K

kustomvette

Guest
yes sidepipes are the way to go.my fatherin law has them on his 74 and they have the deepest, most awesome rumble you ever heard. but yes they are expensive.
 
V

vettes-xlr8

Guest
Thanks for all of tthe great suggestions and the tips on reducing my backfire problem. The smog system was removed long ago but I bet that the carb could be leaned out a bit. I am not sure which direction I'll take but I have some time as it's the dead of winter here in new england and the vette hasn't been out of the garage in over a month.

So, if anyone has any more suggestions, please post them, I really appreciate all of your help.
 
6

69vettester

Guest
Vettes-xlr8,
your problem will be Its easier to troubleshoot if you start with the timing before moving to the Carb.
Make sure your distributor is working correctly.
Like the centrifical advance is not sticking
the vacuum line is sealed.. ,
If all that is go, then get a timing light,
disconnect and plug the vacuum advance on the dist. and see what the initial advance is set at on your motor.
Since your troubleshooting and not fine tunning , back off the initial advance maybe to 4-6 idleing at 800rpms,
this will make for a very small advance curve.
Your motor will definitly not be optimal, but will allow you to troubleshoot the backfire problem.
then Adjust the idle for smooth running, connect the vacuum adv. back up. and test drive.
If the back fire is gone, your problem was too much advance. in that case go back to step one and start advancing the timming a few degrees at a time until you find it running great out on the road. A stock GM SB should run fine with initial advance set at 8-10. but you will need to determine this setting. stronger motors with performance upgrades ect can be dialed in with greater advance curves which optimizes the motors performance.
If this procedure made no difference with you problem, set the timming back to where it was and move on to the carb being the culprit.
Hope this helps..
TC
 
R

rpounds

Guest
Bit of a side note to TC's post . . . if your timing is retarded a little too far so that the engine is laboring, it will have a dramatic effect on the decibel level of the car at the exhaust and the resonance inside the cockpit. Advance the timing a few degrees at a time until you find the optimal running combination. It really will make a huge difference in your sound . . .

RP
 

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