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Author Topic: 1969 DOHC 426 Hemi Prototype  (Read 4163 times)

Offline BacardiCBR

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1969 DOHC 426 Hemi Prototype
« on: June 26, 2008 - 02:57:07 PM »
Has anyone heard of this?  In highschool, I read about this engine somewhere (I can't remember).  As I recall, two of these prototype dual overhead cam hemi's were created and never put in production.  It seemed that the reason was that Mopar and Nascar had their falling out and the motor was intended to compete in that series.

Any info or especially PICS would be great  :cheers:
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1969 DOHC 426 Hemi Prototype
« on: June 26, 2008 - 02:57:07 PM »



Offline 71bigblock

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #1 on: June 26, 2008 - 08:56:18 PM »
This was just discussed in another section, too lazy to look for it now, maybe someone else can find it...   :icon16:

nivvy

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #2 on: June 26, 2008 - 09:12:30 PM »
yes its trui guess... i saw it in a mopar muclse mag......

http://www.thehemi.com/forums/viewtopic.php?p=6211&sid=eff232927684c4cda6bd81d328094bc8
« Last Edit: June 26, 2008 - 09:16:14 PM by StRoKer »

Offline Hot_Rodder

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #3 on: June 27, 2008 - 12:07:46 AM »
I had heard mentions of this motor, guess it is true afterall.... Wonder how it would have done.... :clueless:

Offline BacardiCBR

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #4 on: June 27, 2008 - 08:23:54 AM »
yes its trui guess... i saw it in a mopar muclse mag......

http://www.thehemi.com/forums/viewtopic.php?p=6211&sid=eff232927684c4cda6bd81d328094bc8


Sweet!  So I didn't just dream it up all that time ago!  I was wondering if the responses were going to be something like "Hey Bacardi, maybe you should set the crack pipe down".  Sounds like I could have done a search for it, had no idea it was brought up recently.  Thanks for posting pics  :woo:
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Offline jvike

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #5 on: June 27, 2008 - 09:23:24 AM »
I read somewhere (maybe allpar.com) that the DOHC Hemi was a response to the Ford 427 SOHC "Cammer", when this engine was forbidded in NASCAR, Moper stopped the development of the DOHC Hemi.
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Offline Super Blue 72

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #6 on: June 27, 2008 - 10:14:14 AM »
I read somewhere (maybe allpar.com) that the DOHC Hemi was a response to the Ford 427 SOHC "Cammer", when this engine was forbidded in NASCAR, Moper stopped the development of the DOHC Hemi.


From Allpar...

Dual overhead cam HemiA 426 dual-overhead cam Hemi was actually produced - two of them, in fact, and both were made in 1964. The DOHC Hemis were made to counter Ford's response to the 1964 426 Hemi, the 427 SOHC, but when NASCAR ruled against Ford's engine, there was no need for the overhead-cam Hemi.

Neither of the DOHC Hemis were ever placed in a car; one was destroyed, the other moved to the Kansas City area. (source: Muscle Car Review. Thanks, Stphanie Dumas.) Recently, famed engine builder Larry Shepard told us that he has the A-925 cylinder head and other related parts, purchased from the late Dan Napp.

An article by Tom Shaw in Mopar Muscle went into more detail. The DOHC Hemi was project A-925, and it would need to be much more powerful than Ford's SOHC 427, but still rugged enough for racing - and able to conform to NASCAR's rules. Two possibilities were considered, according to Shaw - one using two cams positioned between the heads, in the "valley;" four valves on each cylinder were operated by lifters, pushrods, and lifters. This expensive setup was an unused contingency plan. Nearly as ambitious was an engine with aluminum heads, dual overhead cams, and, again, four valves per cylinder, with pent-roof chambers. (Chrysler had been working with four valve per cylinder engines for a never-completed Indy run in 1963.)

The dual-plane intake manifold had eight runners per side (Chrysler was into efficient and innovative intakes) and made of magnesium - but designed for a single four-barrel carburetor, as required by NASCAR.

The cams were driven by a cog belt, using external cog wheels at the front of the heads. Because the cams were directly above the valves, valvetrain mass was low, so the engine could rev high - a 7,000 rpm redline was specified, high for the era.

Shaw wrote that no DOHC Hemi ran under its own power; they were driven by an electric motor to check the valvegear. Research stopped in 1964 when NASCAR banned the SOHC 427 and Chrysler's own race Hemi. One DOHC Hemi still exists.

DOHC Hemi Update: Jon Field wrote that there was a third (at least) DOHC Hemi made and that he owns it, a 301 cid aluminum-block-and-head engine with twin cams, two cam covers on each head (the plugs are between them), hydraulic tappets, brass valve seats, and four Weber two-barrel carbs (165 cfm each). He says the oil pan holds 10.6 quarts, and that the engine has stainless steel headers, and an aluminum intake; it is apparently functional and runs on regular gas. We don't have any information on where it came from and whether it's a Chrysler effort or an aftermarket modification.

Here's a pic someone made in 1/24 scale for a '70 Super Bee model:
1972 Dodge Challenger Rallye 340, AT, Code TB3=Super Blue, SBD=8/17/1971.  Yes, a Rallye without the fender louvers from the factory because of the body side molding option.

Pic #2 and 3 of my ARII 1/24 scale model car 

Phil in New England-Massachusetts  Always thank God for what you have!

http://www.cardomain.com/ride/456046/1972-dodge-challenger

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Re: 1969 DOHC 426 Hemi Prototype
« Reply #6 on: June 27, 2008 - 10:14:14 AM »