1969 Smokey Yunick Camaro

[69 Post Sedan]

A friend of mine (Boomer) took these pictures of a 1969 Smokey Yunick 302 Hemi Z28 at the Street Machine Nationals in St. Paul, MN.

Kurt

[William]

600 hp? What's he on? ZL-1 engines still don't do that.

The problem with the hemi head was that it made no more power than the standard head. Back in the day a Traco X-ram 302 was at maybe 425 hp. Chevy gave up on the hemi and passed it on to Smokey Yunick; the reason parts still exist. He gave up on it also and called it "...a one half-million dollar trip to $hitsville" in his book.

[John Brown]

Car show cars all make more horsepower than ordinary cars. [img]<<GRAEMLIN_URL>>/rolleyes.gif[/img]

[Verne_Frantz]

I'll bet those intake gaskets are hard to come by.....
Verne [img]<<GRAEMLIN_URL>>/wink.gif[/img]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: John Brown</div><div class="ubbcode-body">Car show cars all make more horsepower than ordinary cars. [img]<<GRAEMLIN_URL>>/rolleyes.gif[/img] </div></div>

L-O-L!

And as near as my research can show, it was a canted valve combination. Not a hemi. But what do I know?

Wayne

[smallblockhero]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hotrodsled</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: John Brown</div><div class="ubbcode-body">Car show cars all make more horsepower than ordinary cars. [img]<<GRAEMLIN_URL>>/rolleyes.gif[/img] </div></div>

L-O-L!

And as near as my research can show, it was a canted valve combination. Not a hemi. But what do I know?

Wayne </div></div>

that exactly right. i talked to smokey years ago about this head set up for about 2 hours. he said himself that these heads generally made 10-15hp less then what the tracos were making at that time period. he told me he had hundreds if not a thousand man hours into this design only to turn out to be fruitless.

[Carleen]

http://www.guinns-engineering.com/Quang%20Le%20Hemi.htm

http://ricksclassics.com/one/00-One/cortez.html

Hi... just because someone (or a website or two) claims they are &quot;hemi heads&quot;, I wouldn't be too quick to believe it. I suspect if you saw the combustion chambers on those so-called &quot;hemi&quot; heads you'd change your mind pretty quickly...L-O-L.

Keep in mind that: A hemi generally needs a central plug location. A hemi needs a large bulky rocker arm assembly. The valve cover would have to be very (very) wide to allow for the valve arrangement on a hemi small block head. On the other hand, Chevy pretty much had a background in Canted Valve or &quot;Semi Hemi&quot; heads in the rat motor family at the time. The canted valve design does not mandate a central plug location nor does it mandate a convoluted rocker arm arrangement that would require a comprehensive cylinder block revision. And a canted valve setup could use a valve cover that was, for all intents and purposes shaped like a little rat motor piece. Following right along, a canted valve 90-degree V6 and then a canted valve small block head was released by GMPP years later that with revised ports looked suspiciously close to the head on the Yunick engine. I suspect if you do some additional research you'll find that this was a canted valve small block cylinder head that Yunick, Jenkins and others were playing with at the time. In fact, I think you'll discover that Jenkins even messed with them in his Vega/Monza era.

And I too discussed these heads with Smokey at length (anyone who knew him in later years will tell you he was pretty free with information).


Wayne

Forgot something...

I agree...Smokey also told me the heads were actually down on power. If you look at one of the old Jenkins small block Chevy books, there's a picture of the Grump fiddling with what looks like a 351 Cleveland tunnel ram on a small block. Back then it wasn't easy or practical to fab an intake (sheetmetal). I suspect he was trying to figure out how to adapt the intake to a set of these heads.

Wayne

[iluv69s]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Hotrodsled</div><div class="ubbcode-body"><div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: John Brown</div><div class="ubbcode-body">Car show cars all make more horsepower than ordinary cars. [img]<<GRAEMLIN_URL>>/rolleyes.gif[/img] </div></div>

L-O-L!

And as near as my research can show, it was a canted valve combination. Not a hemi. But what do I know?

Wayne </div></div>

With all due repect to those of you out there that have spoken to Smokey himself and that are more knowledgeable than me.I respectfully disagree on two points.

First, I just looked at my heads here and they sure look like a hemi head to me....what is actually the difference in a hemi head or a semi-hemi head anyway??? the chambers are completely round and the spark plug hole is in the center of the valves and close to the center of the chamber. Maybe they are not as deep a chamber as a chrysler hemi head???

Second,....I am getting ready to build my motor to put in my 67 Z and I am planning on seeing if I can get 600 plus horses out of my heads !!!