C2(64) Exhaust - need some experience

[Larry M.]

I just recieved my new exhaust from Corvette Central (N11 with carbon steel pipes). The rule of thumb is go slow to go fast. This is the go slow part. I'd rather be on my back putting them on.

Be assured, this is not about bashing CC. They may be great and a great supporter of NCRS, but I want to be sure before I go forward.

As background:I considered Allen and CC and used CC because of posts that said they had less fit isses.

Secondly, this car once had sidepipes and where the system on it came from I don't know but I "think" it is potentially an original exhaust system. Your responses may shed light on this. So here are my questions and issues:

1. See picture below - StraightSect. The tailpipes I took off are formed to create somewhat of a retangular shape with two lines of tooling marks on the top and bottom. I think this is very much original. The pipes from CC have only one tooling line and are very oval in shape in the straight sections. Is this as good as I'm going to get? Is it more correct than what I have?

2.When you match the mufflers up the left system is longer than the old one (see picture LeftLength2), and the old left one is similar to the right. The new right side if fairly close in length to the old one. Maybe I can make this up in the joint adjustment and the rear hanger, but does this look like a serious issue to you? I'm thinking it is.

3. The tailpipe extensions rear of the muffler on both sides are about 5.25 inches whereas the old ones are 4.5 inches ( this may be manageable). The old ones have no visible weld (welded inside). The new ones have a pipe welded inside a nipple (see picture DetailRtRr). Which is more correct, the old or the new? Can I do better with a different vendor? Both of my old ones have the pipe welded to an extension on the forward end of the muffler similar to what CC supplied, although their extensions are much longer than what I have. How were tailpipes and rear extension welded to the mufflers (e.g., is the old or the new in the picture correct)?

4. It may be hard to see in the picture (ExhAngle), bu the new ones slant up to the fender more than the old ones. This gets back to the question: do the old ones look correct? What do you think and can/should I do better?

Any help or comment on this would be appreciated.

[Alan D.]

Re: C2(64) Exhaust - need some experience

So do you see any details on the muffler itself (yours?) Any remains of yellow something?
Here is a short of the end of a NOS system purchased in 1970. If nobody is able to supply some dimensional data I can get back to you over weekend. There's a lot on info on these things, so try some searches.

[Edward J.]

Re: C2(64) Exhaust - need some experience

Larry, sometimes when you lay a exhaust on top of a existing one the length may look as if it maybe different. I would try to install the system and see how it fits. I use a corvette central N11 system on my 63 and no problems. and had a friend that used C.C. it to with no issues. I thought it was one of the best exhaust systems for fit and really looks great, It tucks up nicely and exits the rear at center.

[John M.]

Re: C2(64) Exhaust - need some experience

Larry, Sorry to say that my experiences, 2, with CC were not so good. Same setup as yours for a 65; the left side engine pipe was about 1" too long. It ended up that by the time you got back to the spare tire tub the pipe hit the tub and could not be installed. After saying it was not possible, they use jigs etc, they called back and said they could replce it in a "couple of weeks". I had no time so I cut a 1" piece out of the second pipe and welded the cuff back on. Two wrong pieces now make the right length.
The other issue was the hanger bracket on another car that was off by an inch causing us to severely modify the hanger.
I know mistakes happen but I don't like being called wrong when it's so obvious that they screwed up. Someone else next time.

[Joe L.]

Re: C2(64) Exhaust - need some experience

I just recieved my new exhaust from Corvette Central (N11 with carbon steel pipes). The rule of thumb is go slow to go fast. This is the go slow part. I'd rather be on my back putting them on.

Be assured, this is not about bashing CC. They may be great and a great supporter of NCRS, but I want to be sure before I go forward.

As background:I considered Allen and CC and used CC because of posts that said they had less fit isses.

Secondly, this car once had sidepipes and where the system on it came from I don't know but I "think" it is potentially an original exhaust system. Your responses may shed light on this. So here are my questions and issues:

1. See picture below - StraightSect. The tailpipes I took off are formed to create somewhat of a retangular shape with two lines of tooling marks on the top and bottom. I think this is very much original. The pipes from CC have only one tooling line and are very oval in shape in the straight sections. Is this as good as I'm going to get? Is it more correct than what I have?

2.When you match the mufflers up the left system is longer than the old one (see picture LeftLength2), and the old left one is similar to the right. The new right side if fairly close in length to the old one. Maybe I can make this up in the joint adjustment and the rear hanger, but does this look like a serious issue to you? I'm thinking it is.

3. The tailpipe extensions rear of the muffler on both sides are about 5.25 inches whereas the old ones are 4.5 inches ( this may be manageable). The old ones have no visible weld (welded inside). The new ones have a pipe welded inside a nipple (see picture DetailRtRr). Which is more correct, the old or the new? Can I do better with a different vendor? Both of my old ones have the pipe welded to an extension on the forward end of the muffler similar to what CC supplied, although their extensions are much longer than what I have. How were tailpipes and rear extension welded to the mufflers (e.g., is the old or the new in the picture correct)?

4. It may be hard to see in the picture (ExhAngle), bu the new ones slant up to the fender more than the old ones. This gets back to the question: do the old ones look correct? What do you think and can/should I do better?

Any help or comment on this would be appreciated.

Larry------


1) The configuration of the old pipe appears correct to me. I believe these pipes were die-formed. I don't see any other way that the configuration seen on the original pipes (or GM SERVICE pipes when they were available) could be achieved. I also expect that's why none of the reproduction exhaust manufacturers today can produce an exhaust pipe that's exactly like original. To do it they'd have to fabricate dies and such dies would be prohibitively expensive considering the size of the market today. So, they try to simulate original configuration using other methods and it just doesn't come out as-original no matter how hard they try.

2) Fitting an exhaust system to a car is more of an art than a science;

3) The configuration of the attachment of the rear exhaust tip extension on the old muffler is correct. The configuration on the new muffler is incorrect.

Trying to achieve an exactly correct exhaust system configuration using ANY parts available today, including virtually all NOS, is impossible. Period.

One other thing.: you did not picture the forward end of the old mufflers, including the attached exhaust pipe. That would be necessary to opine on the correctness or origins of the old system.

[Larry M.]

Re: C2(64) Exhaust - need some experience

Joe, I really appreciate your answers. They are directly responsive to my questions. Attached are the pics of the inlets. The nipples on the new ones are longer than the old but the old one have nipples, clearly visible on one and not so much but there on the other. What do you think about the originality of this system? If not original, could it be the original tailpipes with service mufflers welded to them?

As an aside, and you don't need to read this, I don't know where these exhaust came from. I'm relatively positive the original owner had sidepipes. It goes with his car personality and convincing details on the car (lower front fender tips cut off(luckily the backs weren't), rocker support brackets cut off or bent out of the way, bracket holes in the inner fenders, etc). And he had a radio installed in a factory non-radio car, had the 3rd taillights and had headrests installed. Some of this got reversed in a "restoration" prior to by getting the car and I'm working on the rest. But on the other hand, when he sold the car at 37500 miles he sent virtually everything with it....title, BOS, window sticker, license plates, registrations, maint receipts, original temporary tag, owner packet, letters between he and GM, etc, etc. So I wouldn't be surprised if he didn't sent the original exhaust thay he took off when he put on pipes. On the other hand, I don't think he sent the original rocker molding..the ones on the car are too nice. We never know for sure what he did. But while I'm rambling, one thing I really like on the car. He had 5 dealer installed KOs with 5 6.70X15 Michelin X radials, and I have them, still in serviceable condition. Have driven them some....but I've owned the car about 13 years and I've only put 1000 miles on it.

[Joe L.]

Re: C2(64) Exhaust - need some experience

Joe, I really appreciate your answers. They are directly responsive to my questions. Attached are the pics of the inlets. The nipples on the new ones are longer than the old but the old one have nipples, clearly visible on one and not so much but there on the other. What do you think about the originality of this system? If not original, could it be the original tailpipes with service mufflers welded to them?

As an aside, and you don't need to read this, I don't know where these exhaust came from. I'm relatively positive the original owner had sidepipes. It goes with his car personality and convincing details on the car (lower front fender tips cut off(luckily the backs weren't), rocker support brackets cut off or bent out of the way, bracket holes in the inner fenders, etc). And he had a radio installed in a factory non-radio car, had the 3rd taillights and had headrests installed. Some of this got reversed in a "restoration" prior to by getting the car and I'm working on the rest. But on the other hand, when he sold the car at 37500 miles he sent virtually everything with it....title, BOS, window sticker, license plates, registrations, maint receipts, original temporary tag, owner packet, letters between he and GM, etc, etc. So I wouldn't be surprised if he didn't sent the original exhaust thay he took off when he put on pipes. On the other hand, I don't think he sent the original rocker molding..the ones on the car are too nice. We never know for sure what he did. But while I'm rambling, one thing I really like on the car. He had 5 dealer installed KOs with 5 6.70X15 Michelin X radials, and I have them, still in serviceable condition. Have driven them some....but I've owned the car about 13 years and I've only put 1000 miles on it.

Larry------


The old exhaust system appears to be of original configuration. That implies it's a PRODUCTION system. However, if the system is a 2-1/2" system (I can't tell for sure from the photos), it could have been GM SERVICE N-11 muffler/pipe assemblies. If it's a 2" system, it pretty much means it's an original system as installed on a car on the assembly line. This would be quite unusual since it would be extremely rare for a left (driver) side muffler to survive from 1964 to 2013. It's of course possible that it was an original system removed from the car to make way for the installation of side exhaust and then returned to the car after years in "hibernation". Even still, it would be unusual for the left side muffler to have survived. Internal corrosion, once started, proceeds inexorably even in hibernation.

[Larry M.]

Re: C2(64) Exhaust - need some experience

Joe, I plan to keep this system. I'd repair it if I could. The issue is that the left rear extension has come loose and can be easily moved by hand. This allowed movement in the rear hanger and the the SS extension would knock against the bezel. I could cut a hole in the top and weld it from the inside and patch but that likely would only be short lived. Any suggestions. It is a 2 1/2 inch system and, "if" it were the original for the car, it would not be N-11 as that is not on the window sticker.

On the other hand, it makes a nice peice to send pictures of to others who are interested. What do you think?

[Joe L.]

Re: C2(64) Exhaust - need some experience

Joe, I plan to keep this system. I'd repair it if I could. The issue is that the left rear extension has come loose and can be easily moved by hand. This allowed movement in the rear hanger and the the SS extension would knock against the bezel. I could cut a hole in the top and weld it from the inside and patch but that likely would only be short lived. Any suggestions. It is a 2 1/2 inch system and, "if" it were the original for the car, it would not be N-11 as that is not on the window sticker.

On the other hand, it makes a nice peice to send pictures of to others who are interested. What do you think?

Larry-----


I expect that the reason that the rear extension is loose is that the muffler is rotted-out internally. Mufflers usually deteriorate from the indide-out. As you surmise, a repair is likely to be VERY short-lived.

It could be that an N-11 SERVICE assembly was added to the car at some point N-11 SERVICE assemblies were an assembled exhaust pipe and muffler, exactly the same as used in PRODUCTION. No other SERVICE mufflers were available from GM this way. Check the outside shell of the muffler. If you find a raised "W", the chances are it is a standard muffler. If there is a raised "A", the chances are it's N-11. Not for certain, but chances are.

[Larry M.]

Re: C2(64) Exhaust - need some experience

Joe - there is no raised letter on either muffler. Also, I looked at the spec sheet on mufflers that you or Duke or John posted in the past. It says the right is SS shell and alumized cover. Which is on the outside, the shell or the cover?

[Larry M.]

Re: C2(64) Exhaust - need some experience

And a further update - a weak magnet will stick to all four old endcaps and both outer shells.....I don't "think" I have any exposed stainless....again, I said a weak magnet so I don't "think" it is picking up inner stuff, but it might be.

[Jim D.]

Re: C2(64) Exhaust - need some experience

Larry, Sorry to say that my experiences, 2, with CC were not so good. Same setup as yours for a 65; the left side engine pipe was about 1" too long. It ended up that by the time you got back to the spare tire tub the pipe hit the tub and could not be installed. After saying it was not possible, they use jigs etc, they called back and said they could replce it in a "couple of weeks". I had no time so I cut a 1" piece out of the second pipe and welded the cuff back on. Two wrong pieces now make the right length.
The other issue was the hanger bracket on another car that was off by an inch causing us to severely modify the hanger.
I know mistakes happen but I don't like being called wrong when it's so obvious that they screwed up. Someone else next time.

I had the same problems with my CC exhaust for my 65. I had to cut both sides to get it to fit and had to have a muffler shop do some additional modifications. On the other hand, the CC exhaust for my C-3 BB car fit perfectly.

[John H.]

Re: C2(64) Exhaust - need some experience

Also, I looked at the spec sheet on mufflers that you or Duke or John posted in the past. It says the right is SS shell and alumized cover. Which is on the outside, the shell or the cover?

Larry -

The Engineering specs I posted are for '67 - don't have them for '64, don't know if '64 was the same or different. The "shell" is the inner portion of the muffler, which is covered by an asbestos-based "wrap", then the outer "cover"; the "cover" is what you see, and is aluminized steel. The RH muffler shell was stainless, as were two of the four internal baffles, plus the front and rear caps. The LH muffler was all aluminized steel.

Also note that from a judging point perspective, the pipes and mufflers only carry 10 originality points (vs. 25 for a lighter that doesn't "pop" or washers that don't squirt), so the inevitable exhaust deductions for replacement or reproduction systems are very minor in the grand scheme of things.

[Ken R.]

Re: C2(64) Exhaust - need some experience

I purchased a new set of service replacement mufflers for my 65 from GM in 1990's. Think they were some of the last NOS sets as one came from PA parts center and other one from Lansing center as I remember. Anyway there were identical to my original set as I remember. Here are some photos I took of them few years later.

https://picasaweb.google.com/Karman1965/65Mufflers2006_07_15

Front part of pipe is "square", not round. I had heard that GM used hydro-forming to do this shape.

[Joe L.]

Re: C2(64) Exhaust - need some experience

I purchased a new set of service replacement mufflers for my 65 from GM in 1990's. Think they were some of the last NOS sets as one came from PA parts center and other one from Lansing center as I remember. Anyway there were identical to my original set as I remember. Here are some photos I took of them few years later.

https://picasaweb.google.com/Karman1965/65Mufflers2006_07_15

Front part of pipe is "square", not round. I had heard that GM used hydro-forming to do this shape.

Ken-----


This is an "off-road" N-11 system. It's the only exhaust system that was available from GM in its original PRODUCTION configuration (i.e. rear exhaust pipe welded to muffler with no slip joint).