They Never built it #2

[MO]

Piggins was trying to win approval on special performance parts he wanted to use in the SCCA’s Trans-Am racing series. He built a Camaro ragtop, added the special parts and put it in the Executive Garage knowing Estes would try it out and OK the parts as production options, making them legal for racing.

That version has been repeated so often it is accepted as fact.

The chronology of the concept, design, development and availability of the cross-ram intake and Corvette 4-wheel disc brakes is available in an excellent book written by Wayne Guinn “Camaro Untold Secrets” written many years ago.

Development work on 4 wheel discs began very early in 1968 as evidenced by several Chevrolet engineering drawings dated January 1968. It was released as an off-road part March 1968.

Development work on the cross-ram intake began late in 1967. Documents discussing a dyno comparison between the stock 1 x 4 system and a fabricated 2 x 4 system are dated August 8, 1967. The earliest production-type manifolds had casting dates of October 21, 1967. The cross-ram was released at the same time as the 4-wheel disc brake option; the instruction sheet is dated March 20, 1968. 

Both of these new systems were featured in the May 1968 Hot Rod magazine in an article titled "Just For Fun: 68 1/2 Chevys". Car & Driver tested a cross-ram/JL8 '68 Z/28 in the July '68 issue. Magazine lead times were about 3 months so these events took place around March 1968. 

There is no way this car, built 4 months AFTER the release of 4 wheel discs and the cross-ram had anything to do with them. It was retrofitted with a cross-ram and 4 wheel discs for display at race tracks hosting T/A races later in ’68. That equipment was not on the car when it was sold December 17, 1968.

Body tag indicates the car was built British Green, white convertible top, white custom interior. Should have a white top boot.

Funny, I assumed the build date in the article was wrong. Surprising to build that car so close to 69 production.

[David K]

So interesting to learn new stuff about this car, and I’m glad to see people add in. The dealer sheet to owner #1 is cool. However, it states Z28 on the RPO list so I’m a little confused. So I wonder, if this car wasn’t equipped with Z28 parts from the assembly line, what did it have? We’ll never know, but I’m guessing an SS 350 with the same steering/ brakes/rear a Z would have. It’s already equipped with the bones.

[william]

It was built as a Z/28. The cross-ram and 4-wheel disc brakes were added and removed.

[Charley]

And Mecum still owns it......

[MO]

So interesting to learn new stuff about this car, and I’m glad to see people add in. The dealer sheet to owner #1 is cool. However, it states Z28 on the RPO list so I’m a little confused. So I wonder, if this car wasn’t equipped with Z28 parts from the assembly line, what did it have? We’ll never know, but I’m guessing an SS 350 with the same steering/ brakes/rear a Z would have. It’s already equipped with the bones.

Definitely built as a Z28. See post 6 by William for verification. 

[David K]

I trying to understand what consisted of “Special parts” and “it didn’t originally come with performance options” that were added and then removed. There’s a lot of misinformation that’s been passed along for years.

[william]

For the '68 model year, 4-wheel disc brakes were over the counter only, no production cars built with it. As of January '69, RPO JL8 [4-wheel discs] became available to order.

The cross-ram intake was never a production option.

[David K]

So the AIM is wrong? Headers—tossed in the trunk with the cross ram. But JL8 is shown to be available.

[169INDY]

1968 Model Year: (*or others as applicable) Topic Never Built #2 1968 Z28 Convrt
Exhaust Headers avail as RPO or service
RPO Z283 & Z284 would include in trunk
Some Books use term such as "Factory Installed" which is defined as '*placed and located in trunk at the factory' vice Installed onto engine assembly.

Cross-Ram Manifold (2X4) intake: "Such a system would be offered to the public, but only as a service part, not as a factory *installed option."

Just because a RPO option is "Illustrated" in the AIM does not necessary indicate actual availability.   (# I think Kurt recently posted documentation from Chev that clearly indicated RPO JL8 was deferred to the Model year 1969 for availability.)

Just a bunch of thoughts above. Others will certainly correct my details.

The Subject Car is an amazing part of F body history for sure

[David K]

True. I am still on the hunt for the elusive and complete AIM…all pages, all RPO pages shown.

[Gars68Tux]

So the AIM is wrong? Headers—tossed in the trunk with the cross ram. But JL8 is shown to be available.

Headers in the trunk (if ordered) for 67-8 Z/28 only, as they were a factory RPO, but not installed. Was cancelled for 69. Same goes for cowl plenum intake, Z/28 only RPO, tossed in the trunk, cancelled in 69.

As mentioned, Cross Ram never was a factory option. "Over the counter" only.

[Gars68Tux]

True. I am still on the hunt for the elusive and complete AIM…all pages, all RPO pages shown.

Is there such a thing?

[william]

Headers and plenum air intake cancelled January 19, 1968.

[Gars68Tux]

Thanks William! So those options (RPO's) only lasted for aprox one calendar year (12 months)...?

[william]

Looks that way.

Maybe offered to legitimize the equipment in the eyes of the FIA/SCCA. Headers were very expensive [$421] and there were much cheaper alternatives.

Once spoke with the Chevrolet Engineer that did much of the work on the JL8 option, Gib Hufstader. He said the SCCA believed Chevy had mislead them into thinking 4-wheel discs was a production option for '68 and were intent on not allowing it for the '69 season. They had to show a JL8 car in stock at a dealer to get them to back off. Wonder if the JL8 section of the '68 AIM was just there to make it look real.

JL8 is an interesting story. In competition, the '67 Penske T/A Camaros were experiencing severe brake fade. Some quick fixes didn't help. Engineering assumed the production disc/drum brakes were inadequate for racing and began a crash program to adapt Corvette disc brakes to the Camaro. Didn't fix the problem; still had a hard pedal and no brakes. The root cause turned out to be inadequate fluid capacity in the system. When the brakes heated up, there was no fluid remaining in the front reservoir in the master. The rear reservoir was larger, all they had to do was switch the lines at the master. Problem solved.

All that and much more in Paul Van Valkenburg's excellent book Chevrolet=Racing?