They Never built it #2

[169INDY]

^^  Road & Track "Road Test" June 1968 Issue.  (*Also same car in Car Life "Road Test" July 1968 issue)^^
Performance Package $400.25

Those were Smog headers;

Text from Article: "Our Test Car Also had, as its only item from the "dealer" list, a set of tuned headers (Installed by Bill Thomas Race Cars) as these are never installed at the factory anyway) which added another $200 anyway."

I believe the Author was referring to INSTALLED on the engine?

Could the Test car been supplied with Factory headers that were then modified to conform to Calif (SMOG) & installed  and subsequently for test review.

[Gars68Tux]

Thanks Jim, been a long while since I read it! So I take it, they were probably sold "over the counter" then?

[GMAD_Van Nuys]

The Car & Driver article of the 1968 Z28 vs 1968 Tunnel Port Mustang was one of my favorites:

https://www.caranddriver.com/reviews/comparison-test/a15142639/1968-tunnel-port-ford-mustang-vs-chevrolet-camaro-z-28-archived-comparison/

I didn't see any smog pump on the Z28 in the Car & Driver article and neither car had California license plates. 

[KurtS]

Wonder if the JL8 section of the '68 AIM was just there to make it look real.

No, JL8 almost made 68 production. I haven't seen anything about why it didn't.
This is dated May of 68.

[william]

I have wondered about that. If JL8 was truly ready in '68 and bureaucratically delayed, it would have been available at the '69 MY launch. But it wasn't an RPO until the January '69 release of dealer ordering info, seven months later.

My guess, some issue came up in testing that had to be solved. From what I have read, the Penske race cars had chronic rear axle tramp under hard braking with the production disc/drum system. Could be the JL8 system further aggravated it. Penske solved it by changing shock absorber valving.

JL8 also prompted the change from AD to YH wheels for additional caliper clearance on JL8 cars.

[cook_dw]

So is the offset different or is it the center drop off?  As the backspacing on AD & YH are 4.250" from what I have in my notes and the DF is 4.0625"

[william]

They reduced the width of the center drop off.

[KurtS]

I have wondered about that. If JL8 was truly ready in '68 and bureaucratically delayed, it would have been available at the '69 MY launch. But it wasn't an RPO until the January '69 release of dealer ordering info, seven months later.

And you'd think they would have the wheels released correctly for 69 launch, instead of a running change 4 months later...

[68camaroz28]

Som very interesting information.

[Gars68Tux]

^^  Road & Track "Road Test" June 1968 Issue.  (*Also same car in Car Life "Road Test" July 1968 issue)^^

^^  Road & Track "Road Test" June 1968 Issue.  (*Also same car in Car Life "Road Test" July 1968 issue)^^
Performance Package $400.25

Those were Smog headers;

Text from Article: "Our Test Car Also had, as its only item from the "dealer" list, a set of tuned headers (Installed by Bill Thomas Race Cars) as these are never installed at the factory anyway) which added another $200 anyway."

I believe the Author was referring to INSTALLED on the engine?

Could the Test car been supplied with Factory headers that were then modified to conform to Calif (SMOG) & installed  and subsequently for test review.

Those were Smog headers;

Text from Article: "Our Test Car Also had, as its only item from the "dealer" list, a set of tuned headers (Installed by Bill Thomas Race Cars) as these are never installed at the factory anyway) which added another $200 anyway."

I believe the Author was referring to INSTALLED on the engine?

Could the Test car been supplied with Factory headers that were then modified to conform to Calif (SMOG) & installed  and subsequently for test review.

I take it, installed on the engine.

Jim, Chick, Kurt, William...or to whom it may concern. Regarding smog (A.I.R.) headers;

When headers in general (with or w/o smog), were furnished "in the trunk", did they come from the factory or did the dealer add them ?

Is it possible these smog headers were furnished in the trunk ?

Or as Jim suggested, they may've been modified (presumably by Bill Thomas) for special applications ?

Could they (smog headers) be purchased through a dealer, "over the counter"?

67, smog was only required in CA, but 68, ALL Z's had smog. I've always assumed the headers supplied in the trunk of a 68 were NOT smog equipped ? So I guess they were intended for off road use only...

[68camaroz28]

Garth, the number ordered from the factory as we all can assume was pitifully low and they were furnished in the trunk from anything I’ve ever uncovered. Jerry M has an original 68Z that he let me examine out of Reedman Chevrolet that was ordered with the headers. Dealer would not install due to smog system and Jerry said that was common for those along with the air cowl plenum not being installed by dealer. I cannot imagine a dealer cutting into the firewall for plenum install.
I had many conversations with Jere Stahl concerning headers used in 67 thru 69 and at no time was there any mention of smog headers. The smog set of headers would be safe to assume were modified as Jim suggested.
It’s also interesting to note the air cowl plenum did not fit properly with the stock smog system due to passenger side smog tubes interfering with bottom of its air cleaner. Jerry shows a setup of air cowl plenum and what appears stock smog setup but the passenger side smog tubes were changed to a later year nova set which gave the needed clearance. Kind of funny since they put in the indent for smog pump in the air cowl plenum but design wise it was not totally a fit.

[169INDY]

I grabbed the paper copy of the R&T article and in the black and white photo it really does "look" like the header is severely discolored at the point the smog tube meets the header tube indicating welding. (i.e. Air tube riser added to header after paint/mfrg)

[cook_dw]

FWIW, Hooker offered a smog tube kit to be added to any header.  Different manufacturers but the kits were available to be added by anyone.  I don’t recall the part number but it was not a popular item for sale and was discontinued in the late 90’s when the LT1 was replaced by the LS engines.  Going off memory as it’s been almost 15 years since I’ve been at Holley (Hooker tech rep).

[Gars68Tux]

Thanks for the replies, folks, I appreciate it. Hope you all had a wonderful Mothers Day!

 Was basically just wondering if smog type headers could've been purchased or supplied by GM, ready to bolt on without modifications. Sounds like what they did offer, the buyer was basically on their own to make it work as desired. 67 is understandable, but 68 seems odd, being the new 50 state federal emissions requirements. I guess it was such common practice to remove smog systems back then, GM wasn't about to waste any more money than they had to.

[GMAD_Van Nuys]

Garth - My friend's 1968 Z28 had aftermarket headers with the smog fittings which were connected to the smog pump. - Mark