67 427 Side exhaust

[Berndt U.]

Hello
We have a 67" 427 with a side exhaust system. We have a problem with a lot of exhaust noise. I think we have the original parts on this red Convertible. Is this a good Idea to change te muffler to get less noise.?
The Germany Inspection say it is " ZU LAUT ".
Thanks Berndt Berlin- Germany

[Keith G.]

Re: 67 427 Side exhaust

Food for thought, I have a 327 with repro sidepipes that is way louder than my 427 with nos sidepipes, you might have repo on your car.

[Bill M.]

Re: 67 427 Side exhaust

Guten Tag, Berndt

The side exhaust system was called "off-road" by GM, which means it is "zu laut" for street use in the US too!

I've never (in 45 years) been ticketed for "off road" exhaust on a Corvette, but I have been ticketed for "off road" mufflers on a '55 Chevy. I guess the local polizei expect a Corvette to be "zu laut"! (I had to replace the "off-road" mufflers on the '55 Chevy, and the judge listened to them to make sure they were quiet enough.)

[Donald T.]

Re: 67 427 Side exhaust

Guten Tag, Berndt

The side exhaust system was called "off-road" by GM, which means it is "zu laut" for street use in the US too!

I've never (in 45 years) been ticketed for "off road" exhaust on a Corvette, but I have been ticketed for "off road" mufflers on a '55 Chevy. I guess the local polizei expect a Corvette to be "zu laut"! (I had to replace the "off-road" mufflers on the '55 Chevy, and the judge listened to them to make sure they were quiet enough.)

Side exhaust and off road exhaust are two different options (N11 and N14). The off road exhaust is an under car exhaust system where the mufflers had fewer baffles and as a result were louder. Both are louder than the standard exhaust system, but they are completely different animals.

[Paul H.]

Re: 67 427 Side exhaust

To me, listening to factory side exhaust is like music as I drive. I guess noise is in the ear of the beholder but I have always found it pleasing. I wouldn't dream of changing an original side exhaust car to regular exhaust. As stated earlier, "off road" and side are two different options.

[Wayne M.]

Re: 67 427 Side exhaust

Side exhaust and off road exhaust are two different options (N11 and N14). The off road exhaust is an under car exhaust system where the mufflers had fewer baffles and as a result were louder. Both are louder than the standard exhaust system, but they are completely different animals.

GM classifies both exhaust systems as "off-road", probably to protect their legal butts. Still, they never learn (see attached pic of TSB on SS '69 Camaros and Chevelles).

Look at the dealer showroom brochures and the order forms for '66 and '67 Corvettes. N11 is called Off Road Exhaust, and the N14 is called Side Mounted Dual Exhaust (Off Road Service). Not enough room for the latter on the window or tank stickers, though.

[Donald T.]

Re: 67 427 Side exhaust

GM classifies both exhaust systems as "off-road", probably to protect their legal butts. Still, they never learn (see attached pic of TSB on SS '69 Camaros ans Chevelles).

Look at the dealer showroom brochures and the order forms for '66 and '67 Corvettes. N11 is called Off Road Exhaust, and the N14 is called Side Mounted Dual Exhaust (Off Road Service). Not enough room for the latter on the window or tank stickers, though.

That's interesting Wayne. I've never heard that side exhaust was considered off road use, but it certainly makes sense.

[Greg G.]

Re: 67 427 Side exhaust

For what its worth.

I had a friend that was ticketed years ago and went to court and won. The side exhaust were considered original equipment and legal for street use when the car was new, therefore were legal then.

Greg

[Berndt U.]

Re: 67 427 Side exhaust

Thanks for your help.
I think we have a 67 427/435 3x2 Corvette with side exhaust and
L89 option.!! I am not the BB Gay to find out the corr. Cation No. for this engine. But I looks like ALuminium to me.
With this Option the Car has to be original. OR NOT ??
Berndt

[Kevin M.]

Re: 67 427 Side exhaust

Bernt,

The intake manifold may be aluminum, without more details like trim tag PAD stamping and numerous numbers, I don't think you can get a guess here. Now I think it has gone unnoticed that your over seas and it appears the police are giving you hard time. As the posts above have mentioned side exhaust is LOUD and gets louder the further from factory you get. If you have the loophole of being factory to leave them on, get the details mentioned above and these guys will help you out.

KM