69 Z28 Experimental Headers

[camaronut]

Saw these on a 69 Z at a local cruise.  These are quite interesting.  Maybe a Bill Thomas / Kustom kinda thing.  They resemble Doug Thorley Tri-Y headers.
I asked the owner if he knew anything about them - he said they came with the car.

[william]

Looks BS to me. Chevy dropped the option early in the '68 MY.

[Kelley W King]

William, is this where the parts were shipped with car prior to the notice? And available over counter after? Referring to the (shipped in the trunk) story.

[bertfam]

I agree with Bill and also add that the tag doesn't conform to the Chevrolet pre-production (prototype) nomenclature in either the "Build Work Order" or the "O-Dash" formats. Someone took a set of aftermarket headers and welded that tag onto them.

Ed

[william]

William, is this where the parts were shipped with car prior to the notice? And available over counter after? Referring to the (shipped in the trunk) story.

Yes, the letter is dated January 19, 1968. Also noted in the Assembly Manual in the Z/28 section.

[camaronut]

I agree with Bill and also add that the tag doesn't conform to the Chevrolet pre-production (prototype) nomenclature in either the "Build Work Order" or the "O-Dash" formats. Someone took a set of aftermarket headers and welded that tag onto them.

Ed

I just don't know why anyone would go through all that malarkey for a set of headers.  But then again..................

[bertfam]

I just don't know why anyone would go through all that malarkey for a set of headers.

Because they want their car to be "special". Ego plays a lot into this. I'm not a psychologist, but I've seen a lot of strange crap people do (or claim) about their cars over the years!

Ed

[camaronut]

Unless I see some official paperwork / authentic certifications from 1969 - I call this BS!

[maroman]

The tag looks to be brass.

[william]

I just don't know why anyone would go through all that malarkey for a set of headers.

Because they want their car to be "special". Ego plays a lot into this. I'm not a psychologist, but I've seen a lot of strange crap people do (or claim) about their cars over the years!

Ed

No better example than the 'Hemi 302'.

Chevy gave up on it, passed the project on to Smokey Yunick. He gave up on it also, calling it a "...one half-million dollar trip to Shitsville" in his book. Super Chevy did an interview with him in the August 1996 issue. He stated after considerable re-work, the heads topped out at 450 hp, less than his race-prepped production 302s did.

Apparently the truth doesn't apply to those that have them. I have seen a few Z/28s with the heads, claiming 650 hp.

[crossboss]

I just don't know why anyone would go through all that malarkey for a set of headers.

Because they want their car to be "special". Ego plays a lot into this. I'm not a psychologist, but I've seen a lot of strange crap people do (or claim) about their cars over the years!

Ed

No better example than the 'Hemi 302'.

Chevy gave up on it, passed the project on to Smokey Yunick. He gave up on it also, calling it a "...one half-million dollar trip to Shitsville" in his book. Super Chevy did an interview with him in the August 1996 issue. He stated after considerable re-work, the heads topped out at 450 hp, less than his race-prepped production 302s did.

Apparently the truth doesn't apply to those that have them. I have seen a few Z/28s with the heads, claiming 650 hp.

The potential IS there. The Boss 302/Cleveland heads were Chevy's intention to copy it and make tremendous power. Im sure you guys know that Boss 302s and 351 Cleveland's DO make tremendous power...when set up properly. However, that is a different topic. altogether...
Concerning the headers, it appears (to me) they are of a modern design made of stainless steel, with a thick flange. The 'tag' was also added in my opinion. That said, was/is the owner trying to make a claim of an experimental part? OR just for show. Who knows?

[maroman]

Guarendamnedteed if I found a pair of those semi hemi heads that I could afford I would run them regardless of how much hp they made. They look cool and you aren't going to see many others.

[william]

More to them than just the heads. Required block modifications to clear the push rods, different cam and intake.

According to Smokey, the exhaust ports were compromised to clear the head bolts.

[bcmiller]

Way back when, my dad bought a late year 68 Z28. It supposedly had headers in the trunk, and for many years I assumed they were original factory headers. Documentation on when this option ended seems to prove otherwise. But they were there. Just probably not original GM or they were from another car - or aftermarket. Car came from Chicago area originally.

Anyway, they were installed shortly after purchase but are long gone - so no proof.

[crossboss]

More to them than just the heads. Required block modifications to clear the push rods, different cam and intake.

According to Smokey, the exhaust ports were compromised to clear the head bolts.

Guarendamnedteed if I found a pair of those semi hemi heads that I could afford I would run them regardless of how much hp they made. They look cool and you aren't going to see many others.

Tuning small block canted valve heads are a lot different than a set of conventional inline valve heads. Speaking from experience on Boss 302s, the use of a shorter con rod is required to promote velocity for those big ports to work. Second, a camshaft with tight lobe centers around 104-105, and 600 lift with 1.73 rocker ratios. You must think out of the box, and not the conventional 'tuning' as one would do on a small block Chevy. This IS a totally different animal. Yes, it is a Chevy canted valve head. However, it was designed after a close resemblance of the Ford Boss 302s, using the same cubic inches, and bore/stroke. Also, carb selection (and placement) on the intake (and port runner designs) is just as important. Exhaust tube sizing is extremely sensitive on this type of engine.