Some fun Corvette history

Part way through the 1965 Corvette model year the factory started to install the new N14 side mount exhaust option as it was known. Though available for less than a year the option was chosen by 759 of the 1965 Corvette customers. The cost of this option was $134.65 for 1965.

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For the 1966 Corvette model year there was a slight reduction in the price of the N14 option to $131.55 and 3,617 Corvette customers chose this option. The increased order rate reflected the availability of the option for the full 1966 production year.

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With the arrival of the final year of production for the Corvette Sting Ray in 1967 the side mount exhaust was still available. The same cost of $131.65 appeared on the option list. However 4,209 customers chose this option for their 1967 Corvette.
This Sunfire Yellow 1967 Corvette features a 'one off' saddle color interior.

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The 1967 L88 Corvette seems like the perfect vehicle to showcase the final year of the C2 series side mount exhaust system>

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However this Goodwood Green 1967 Corvette L88 General Motors test car featured a more basic side mount exhaust system>

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IMHO, this is one case where the factory OEM looked better than the show car concept.

 

Being a show car the side mount design was a bit 'over the top' for sure!

Noise of course and exhaust gas fumes were an issue with the side mount exhaust. Plus heat was another factor with the metal shields offering minimal protection.
Also the clean look provided by the stock exhaust location was ultimately much more popular with customer.

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This side mount exhaust option however was the choice for the more performance oriented Corvette customers >

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The XP-700 looks like something Brooks Stevens would create on LSD.
*Disclaimer* to my knowledge Brooks Stevens never took LSD or other hallucinogens.

 

Dreaming in technicolor on the right track >

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With the arrival of a new Corvette show car in 1965 called the Mako Shark II there was another chance to feature the popular side mount exhaust system>

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Perhaps but Harley Earl liked that Corvette design so much that he took the Chuck Jordan Corvette and designated it a 'show car'...

 

Bill Mitchell appears with a Mako Shark II Corvette and now no side mount exhaust.

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However there was a plan for the return of the side mount exhaust system to the Corvette option list. Just not for the 1968 model year version as seen in this GM photograph below>

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Brooks Stevens never needed drugs . . . .

*

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This just in: Corvette rated "Most American" of 544 vehicles

For decades, the Chevrolet Corvette has been called “America’s Sports Car.” Now, it also is the “Most American” of automobiles, according to the Kogod Made in America Auto Index, the National Corvette Museum says in a news release.

Criteria used to determine index scores included:

Profit margin – This was measured based on the location of an automaker’s headquarters.

Labor – This category considers where the car is assembled.

Research and development – This category looked at the location of a car’s R&D activities.

Inventory, capital and other expenses – If assembly occurred in the U.S.

Engine – If the engine was produced in the U.S.

Transmission – If the transmission was produced in the U.S.

Body, chassis, and electrical components – Fifty percent of a vehicle’s score was assigned to this category.

https://journal.classiccars.com/2018/08/12/chevrolet-corvette-rated-most-american-car-in-university-study/?utm_campaign=20180813&utm_content=20180813_ds_advertorial_inventory&utm_medium=email&utm_source=zaius&zm64_id=ZW5lcmd5ODhAZWFydGhsaW5rLm5ldA%3D%3D​

 

. . . just condiments

 

Actually, not so much. The factory side exhaust was designed so that it was nearly impossible to burn your leg by accidentally brushing against it while exiting the car. In fact, it was a strict requirement that consumers not burn their leg in order for it to reach production. I have contacted the side exhaust(with full factory shielding in place) many times on my 67 Corvette with zero issue. Not so much with either my Cobra or Corvette equipped with a true "race" side pipe. Additionally, the factory side pipes, while cool, are actually more restrictive than the under body exhaust and reduce power-especially on the big block.. On one of my high power, c2's I had to special order a low restriction side pipe chamber that replaced the factory part while still fitting under the factory shield-big difference! On my 510 powered '69 with side pipes, again, I had to order a special muffler insert as the standard baffle from the header company was so restrictive that the car would hardly run.

 

The Mako Shark was like a spaceship from another planet when it arrived on the scene. I have an early Silva Maco Shark that may be a Motion car-I suppose I should get to work on it.
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Steve thank you for sharing your experiences with the Corvette side mount exhaust systems; great info!

The Silva Maco Shark is a unique piece of Corvette history there, very interesting. Built on a 1971 Corvette?

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Excellent post.
I'm not certain when the change from the closed chamber(3955131) to open chamber(3967832) heads was effective. In a Chevrolet Notice of Production Change No. C69-299 dated 11/26/68, the L88 with M40 automatic was made available using the old closed chamber head. Five L88 class Corvettes with M40 were produced between that date and year end 1968 including the Monaco Orange ZL1. The Notice refers to Stop Order C69-356 I will see if I can locate that document.
A Chevrolet Inter-Organization Letter dated Feb. 6, 1969, Subject: Z.A. Duntov Projects lists two ZL1 development cars(one M22, one M40) and two ZL1 case L88 engines plus spares for consignment for Field Test dated March 21, 1969(Sebring). Further Build Work Order will be issued to get more ZL1 engine assemblies from Tonawanda.

 

Thanks, my Maco was built from an original 427, four speed 69. I should probably track down Joel R and have it verified as a Motion built car while I still can. Many of the indicators are there(early body, evidence of the Hone-O-Drive, grill type, type of fog lights, correct early Ansen wheels with threaded caps, etc)

 

The "Inglewood" tires seemed popular back then to...

 

375+ thank you for sharing these very precise Chevrolet works details about the Z A Duntov Performance Program!
The ZL-1 Corvettes referenced may be the white 1968 press car that seems to have been repainted and with a blue stripe added. Also the Monaco Orange 1969 coupe with the M40 automatic transmission that the press got to drive for the long lead Chevrolet Products preview.
The closed chamber head utilized a half point higher compression ratio than the open chamber heads. My understanding was that the 'open chamber' cylinder head design was done for emission reasons and not for better speed performance.
The ZL-1 Corvettes >

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One more view of the refreshed Zora Duntov ZL-1 press car. The picture appears to be taken at 'Black Lake' on the GM Proving Grounds.

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Another 1968 Corvette though not present was described as Chevrolet Engineering's own development Corvette for competition. This dark color Corvette coupe featured Goodyear road racing tires mounted on American Racing mag wheels and modest added fender flares. Also present was the L88/ZL-1 style hood with no emblem or even hood pins attached. Another unique feature was the clear plastic covers over the exposed headlights plus side mount exhaust headers painted white. Unlike the white Corvette this 1968 Corvette coupe still had it's chrome bumpers attached front and back. This may have been the other road racing Corvette ZL-1 Sebring test car and not the 1969 Monaco Orange coupe with a drag racing suspension set-up. The drag racing Corvette would not be much use at Sebring...

 

I believe that you are correct regarding the identities of the two ZL1s in Zora's skunk works. I can tell you that with an open exhaust the closed chamber heads have an audible edge that the open chamber heads do not. What is the source of the article you just posted? Many thanks!

 

For reference >
The Chevrolet Engineering 1968 Corvette is pictured on page 225 of the Karl Ludvigsen book "Corvette America's Star-Spangled Sports Car". The caption for the picture read 'Not shown was Chevy Engineering's own development car for competition, upper right'. That 1968 Corvette is painted a sort of flat black color.

The 10 Second Trip of course is the Motor Trend article from the October 1969 cover date.

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Thanks, I will pull Karl's book off the shelf.