Question on N-11 exhaust

[Joe L.]

Re: Question on N-11 exhaust

Joe, The right side muffler has

GM

A
11 345 1
Embossed on both sides and the GM paper tag on the pipe has #3845736 for a part number on both sets I have

Greg-------


Well, it's definitely a GM muffler. My opinion is that it should sound exactly like an original, PRODUCTION-line N-11 muffler. It may not to your ear but sound is a very subjective sort of thing. And, it may be that what you're comparing it to is the sound produced by a non-GM muffler.

[Greg W.]

Re: Question on N-11 exhaust

Joe, One last Question. Do you know what the front two pipe #s are off the manifold for a L36 1966. As always thanks so much for the help to a novice.

[Joe L.]

Re: Question on N-11 exhaust

Joe, One last Question. Do you know what the front two pipe #s are off the manifold for a L36 1966. As always thanks so much for the help to a novice.

Greg-------


left side----GM #3869583

right side-----GM #3869584

[Alan D.]

Re: Question on N-11 exhaust

And just to complete the pn, here are the rear L & R parts, notice we have talked about these before;

"John Hinckley, ncrs, 3/8/09
The part numbers for the LH (3845735) and RH (3845736) N-11 assemblies never changed, and the production-line parts and service parts had the same part numbers. The N-11 assembly (muffler and full-length welded intermediate exhaust pipe) was only available as a welded assembly for service; all other service mufflers were just the muffler, with the short curved inlet pipe to be clamped to the cut-off end of the intermediate exhaust pipe."

[Wayne M.]

Re: Question on N-11 exhaust

Wayne------


Which side muffler is this? The part number would be the actual part number for the left side muffler assembly. However, the part number on both of the left side NOS N-11 assemblies I have [none for sale] is 3845737 which is not the part number for EITHER the right or left assembly. I always assumed this was the part number for the muffler component of the assemblies. My right side assemblies are too hard for me to get at but my recollection is that the number is the same. What number is on the other muffler you have?

Here's a few more shots; Second one labelled RH bottom and the third LH bottom. I think the first pic is of the topside.
In a while, I'll lie on my cold garage floor with a mirror to check what's on the tops, if not visible through the wheel opening.

I checked in my 1980 master price book and the list $$ was exactly the same for each side. I'd heard that one side (the left ?) had a stainless steel baffle on the rear head to eliminate corrosion due to condensation that wasn't entirely evaporated by heat from a short run of the motor. Something to do with the heat riser valve causing unequal exhaust distribution until the motor & exhaust system normalized. Maybe just a rumour.

Wasn't able to see the topside clearly, but I'd guess that the same embossed characters are there as well. Would have to take the spare tire carrier off to really see it.

[Greg W.]

Re: Question on N-11 exhaust

Wayne, Are these N-11s original or after 67. The part # on the muffler is correct ,but on my two sets of NOS pipes and mufflers the # on only the left muffler is 3845737. I'm trying to figure out if the change was made after the nos started producing them when production ended in 67.Thank's for your help. Don't pull off the spare tire, NOT worth that. If it makes a difference one set of mine is from 1993 the other 2001.

[Greg W.]

Re: Question on N-11 exhaust

Also Guys, Why would one lose points in judging if the real thing hade embossed #s on the N-11s. I thought only the standard exhaust had no #s?

[Joe L.]

Re: Question on N-11 exhaust

Wayne, Are these N-11s original or after 67. The part # on the muffler is correct ,but on my two sets of NOS pipes and mufflers the # on only the left muffler is 3845737. I'm trying to figure out if the change was made after the nos started producing them when production ended in 67.Thank's for your help. Don't pull off the spare tire, NOT worth that. If it makes a difference one set of mine is from 1993 the other 2001.

Greg-------


Apparently, the embossments varied over the years. I'm a bit surprised that the individual part numbers for the left and right ASSEMBLIES were embossed on the mufflers. As I mentioned, the muffler COMPONENT of the assemblies was the same for either side, the only differences for the assemblies being the welded-on inlet pipes, outlet pipes, and brackets. Apparently, at least at some time, GM required the mufflers to show the embossed part numbers for the assemblies. One would think that this would have been most important when the mufflers were used in PRODUCTION since the standard exhaust assemblies (in PRODUCTION the standard exhaust was supplied as an assembly just like the N-11) would have otherwise appeared identical to the N-11.

[John H.]

Re: Question on N-11 exhaust

Greg-------


Apparently, the embossments varied over the years. I'm a bit surprised that the individual part numbers for the left and right ASSEMBLIES were embossed on the mufflers. As I mentioned, the muffler COMPONENT of the assemblies was the same for either side, the only differences for the assemblies being the welded-on inlet pipes, outlet pipes, and brackets. Apparently, at least at some time, GM required the mufflers to show the embossed part numbers for the assemblies. One would think that this would have been most important when the mufflers were used in PRODUCTION since the standard exhaust assemblies (in PRODUCTION the standard exhaust was supplied as an assembly just like the N-11) would have otherwise appeared identical to the N-11.

Joe -

I'd guess that's why the assembly-line N-11 assemblies had the yellow stencil on the muffler, since that was the only external clue as to whether the part was the standard or the N-11 assembly. The GM drawing for the N-11 assembly has a change note that says the embossed codes and numbers are to appear only on Service parts.

[Joe R.]

Re: Question on N-11 exhaust

Somewhere my thoughts were that Walker Exhaust Systems (a Tenneco company) made the exhaust for Corvettes. Maybe that was just the side pipes as I know the equipment to reproduce them was purchased from Walker.

JR

[Joe L.]

Re: Question on N-11 exhaust

Somewhere my thoughts were that Walker Exhaust Systems (a Tenneco company) made the exhaust for Corvettes. Maybe that was just the side pipes as I know the equipment to reproduce them was purchased from Walker.

JR

JR-------

Walker manufactured most of the Corvette exhaust systems from C1 at least through C3. The only exhaust components that I've seen that were manufactured by Arvin are N-11 systems and I'm not even sure they manufactured all of these.

However, folks don't need to come to the conclusion that if they go out and buy a Walker replacement muffler, they're getting the same thing as GM used and sold in SERVICE. They are definitely NOT the same thing, at all. Once-upon-a-time, though (and I mean a LONG time ago), some of the replacement mufflers available from Walker and Arvin were the same as GM.

[Joe R.]

Re: Question on N-11 exhaust

[However, folks don't need to come to the conclusion that if they go out and buy a Walker replacement muffler, they're getting the same thing as GM used and sold in SERVICE. They are definitely NOT the same thing, at all. Once-upon-a-time, though (and I mean a LONG time ago), some of the replacement mufflers available from Walker and Arvin were the same as GM.[/QUOTE]

Joe,
Isn't that called jumping to a conclusion?????
Water is deep out there!
JR

[Michael J.]

Re: Question on N-11 exhaust

Joe -

I'd guess that's why the assembly-line N-11 assemblies had the yellow stencil on the muffler, since that was the only external clue as to whether the part was the standard or the N-11 assembly. The GM drawing for the N-11 assembly has a change note that says the embossed codes and numbers are to appear only on Service parts.

Thanks John, that fits the part of some TIM&JGs that say only NOS and not originals had part number embossments.