Correct 1967 Corvette exhaust

[Jim W.]

Re: Correct 1967 Corvette exhaust

I had a Zierden system on my '57 - as I recall, their assets were purchased by an outfit named "****Co".

John, You're right. It was MO FO CO (without the spaces). I don't know why the asterisks appear when you type it's six letter name without the spaces. Jim

[John H.]

Re: Correct 1967 Corvette exhaust

John, You're right. It was MO FO CO (without the spaces). I don't know why the asterisks appear when you type it's six letter name without the spaces. Jim

Apparently the censoring robot doesn't like "M O F O" as a word .

[Keith B.]

Re: Correct 1967 Corvette exhaust N11

Charles: If it helps, my 66 BB 427 car came from the factory with N11 "off-road exhaust" I went on this exhaustive search last year for the correct GM mufflers as I have the org steel pipes. After searching, I came up with two for-sale in the $3000 to $6000 price range. Expensive as supply is low. So after much discussion with Allens (great people btw), I went with Corvette Central Aluminized 2.5" with their MAGNAFLOW flow thru mufflers, when CC was offering "free shipping". All I can say is WOW, my BB car breaths and runs better, hp gains, and the sound is a deep growl. I took a minimal hit on judging at the NW NCRS Regional in Sept/07 but the judges (OPS) and fellow members loved the sound. I had them welded, no clamps upon installation. Go to MAGNAFLOW website and listen to their audio/video clips on Chevy muscle cars. I'm very pleased and my car Top Flight'ed at 97.7%......all is well !!

[C M.]

Re: Correct 1967 Corvette exhaust

Once again, thank you to all that participated in this thread. All of this information is greatly appreciated. I think we have enough info here to make a good decision on a replacement exhaust system for our car.

Thanks again,
Chuck

[James G.]

Re: Correct 1967 Corvette exhaust

I would also like to know why no one is puitting the GM part numbers on the mufflers

What I believe is correct is:

ORIGINAL N11 off road exhaust had no part numbers. Now by original, I mean the mufflers that came on the car from Chevrolet.

The part numbered units were Chevrolet service parts that you could buy over the counter for years. Today when you see a NOS part on EBay, chances are it is the numbered unit, and although correct, not the part that came originally. I have seen Allen's, no part # service reproduction get full points in past shows.

I like Gardener products. But they are new to the Corvette hobby and have made great quality products for big Chevrolets, Camaro and Chevelle lines.

Allen has made a good product over the years.

[Jeff S.]

Re: Correct 1967 Corvette exhaust

One thing that never seems to get mentioned is that the N11 system employed double-wall pipe. This would no doubt contribute to the unique exhaust note that originals and service replacements provided. If Allen's & others are trying to duplicate this sound by autoposy on old N11 mufflers, I'm curious if such repro attempts have been with the typical single-wall exhaust tubing.