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Old 01-28-2020, 12:45 PM
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Question Don't think it's been pontiyacked before

V-12..... saw a ls v12 someone put together, so what brand x does ....Pontiac ackers can do better?
Build it and find a fitting poncho to put it in....

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Old 01-28-2020, 12:58 PM
Steve C. Steve C. is online now
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GMC made a V12 engine.
Early 1960s engine was made for heavy trucks .......


https://www.youtube.com/watch?v=hbT4rmlQv9I


.

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Old 01-28-2020, 03:36 PM
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Stick it in a '69 Grand Prix...

K

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Old 01-28-2020, 03:40 PM
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Looking further here is more information regarding the GMC V-12 if interested...

https://www.enginelabs.com/news/a-lo...ix-v12-engine/


Core Engine Sales
V12 core sales. $4,000 per core.

These are v12 engines that have not been disassembled and are of unknown condition and are sold as-is. Expect these cores to be stuck from sitting outside but not blown. They may be runout, just fine or screwed up in any number of ways. Not for the faint of heart.

Disassembled, graded cores are $5k to $10k each. The top of the line being virtually unused N.O.S. engines with good Std Bore and Std/Std cranks...but you rebuild. Call for details.

http://thunderv12.com/thunderv12_gmc_v12_home



.

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'70 TA / 505 cid / same engine but revised ( previous best 10.63 at 127.05 )
Old information here:
http://www.hotrod.com/articles/0712p...tiac-trans-am/

Sponsor of the world's fastest Pontiac powered Ford Fairmont (engine)
5.14 at 140 mph (1/8 mile) , true 10.5 tire, stock type suspension
https://www.youtube.com/watch?v=qDoJnIP3HgE

Last edited by Steve C.; 01-28-2020 at 03:58 PM.
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Old 01-28-2020, 04:41 PM
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Quote:
Originally Posted by Keith Seymore View Post
Stick it in a '69 Grand Prix...

K
Yup

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1963 Cat SD Clone (old school) streeter
1964 GTO post coupe, tripower, 4speed (build)
1965 GTO 389 tripower, 4 speed, driver
1966 GTO dragcar
1966 GTO Ragtop
1969 Tempest ET clone street/strip
1969 GTO Judge RA lll, auto
1969 GTO limelight Conv. 4speed go and show (sold)
1970 GP SSJ
1970 GTO barn find..TLB…390 horse?….yeh, 390
1972 GTO 455 HO, 4 speed, (build)
1973 Grand Safari wagon, 700hp stoplight sleeper
525ci DCI & 609ci LM V head builds
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Old 01-28-2020, 11:36 PM
hurryinhoosier62 hurryinhoosier62 is offline
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The old 60 degree GMC V-12s are nearly impossible to find parts for. I found a really nice ‘65 GMC pickup with the 305 60 degree V-6 in it, but passed on the deal due to the unavailability of common parts, let alone major components like heads, cranks, blocks, rods, etc.

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Old 01-29-2020, 09:47 AM
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For years I've had the thought/fantasy, of building a V16 Pontiac, coupling 2 Stratostreak engines together for a street car. I'll never get to that at age 67.

I have 2 other builds I'd rather do, and will be lucky if I ever get those 2 finished.

Just think of a 800 cubic inch street car (2, 400s in tandem), or if you used 2, 455s, 910 cubic inches...................

A long hooded GP, driving from the rear seat..............LOL

You'd never have to worry about another one showing up at the same show you were attending. Pass everything on the road but a gas station.......LMAO

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Old 01-29-2020, 11:12 AM
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Smokey Yunick talked about the V-12 engines, either in one of his books or in Hot Rod when he had a column there.
They were used a lot in fire trucks, and were not terribly reliable. THey had poor fuel distribution, and would crack exhaust manifolds frequently, and burned pistons may have gone along with that...
Smokey sold GMC trucks (and worked on them...) until 1970

I like the 69 Gran Prix idea, also!!!

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Old 01-29-2020, 01:59 PM
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Quote:
Originally Posted by Sirrotica View Post
For years I've had the thought/fantasy, of building a V16 Pontiac, coupling 2 Stratostreak engines together for a street car...
It would be easier the make a V12 with Sprint heads.

In a more practical sense, leave it to the Aussies


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Old 01-29-2020, 05:00 PM
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Quote:
Originally Posted by 77 TRASHCAN View Post
Smokey Yunick talked about the V-12 engines, either in one of his books or in Hot Rod when he had a column there.
They were used a lot in fire trucks, and were not terribly reliable. THey had poor fuel distribution, and would crack exhaust manifolds frequently, and burned pistons may have gone along with that...
Smokey sold GMC trucks (and worked on them...) until 1970

I like the 69 Gran Prix idea, also!!!
The GMC V-12s were essential two 305 V-6 engines that shared a common block casting. They were loud and fuel hogs but NOT terribly reliable or efficient in making power. They were designed to bridge the gap between the "W"engines(348 and 409) and the two stroke Detroits.

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Old 01-29-2020, 06:49 PM
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The V12 GMC engine was interesting, but totally inappropriate for use in a Pontiac. With the modern aluminum Pontiac style engine blocks and cylinder heads that are available today, a person with enough talent, time and money could saw a few of them up and weld together a V12.

Am I dreaming, or is my memory correct that a V12 or V16 actually was considered in early concepts for the 1969 Grand Prix?

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Old 01-29-2020, 11:05 PM
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Quote:
Originally Posted by Stuart View Post
The V12 GMC engine was interesting, but totally inappropriate for use in a Pontiac. With the modern aluminum Pontiac style engine blocks and cylinder heads that are available today, a person with enough talent, time and money could saw a few of them up and weld together a V12.

Am I dreaming, or is my memory correct that a V12 or V16 actually was considered in early concepts for the 1969 Grand Prix?
Stuart, I like that idea. Two MR-1 aluminum blocks altered and welded together to form a V-12 sounds interesting.

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Old 01-30-2020, 10:30 AM
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Just for clarification, the V16 build I envisioned would not go to all the trouble to mate 2 V8 blocks together with a common crankshaft. It would be 2 V8s that ran a coupler between the 2 V8 engines in tandem. This has been done before with other engines, I.E. Bonneville cars, and some drag cars.

You're going to get the same effect without all the one off parts needed to make 2 engines into one.

The V12 LS engines with a common block and crank are already being produced, so why go to all the trouble and expense to get the same end result? Having 2 V8s in tandem would actually be even a better result without all the added expense of the extra machining and casting to make a V12. You'd have 4 more cylinders and extra length for extra power over the V12. Thing being if it was done with cast iron blocks the car would be so nose heavy that it would only be used for straight line racing, even street driving would be a challenge with most of the weight on the front wheels. Actually getting the car to hook would be most likely an effort in futility. Aluminum engines would help, but in the end it would still be nose heavy.

Given the propensity of Pontiac Stratostreak V8s to run hot with 8 cylinders, cooling a V12 or a V16 with one waterpump and radiator may be the limiting factor to one common block. That's one of the reasons my dream would have 2 sets of waterpumps of 2 engines in tandem, possibly one common radiator, or maybe 2 radiators divorced from each other.

Lots of engineering challenges to make a Stratostreak V12/V16 package even somewhat practical for a street car, not to mention the deep pockets one would need to pull it off, definitely not for the faint of wallet. If someone actually completed a car and engine such as outlined it would still be a exhibition show car type of exercise.

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Old 01-30-2020, 03:42 PM
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Twin engine, a bit easier to do:


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Old 01-30-2020, 07:47 PM
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Heck, if you're going to do two engines why not do four like Mickey Thompson.

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Old 01-30-2020, 10:44 PM
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Quote:
Originally Posted by Stuart View Post
Heck, if you're going to do two engines why not do four like Mickey Thompson.

A little stretch in the middle of those, think a guy could get a seat in there.
Surround sound...ha

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1963 Cat SD Clone (old school) streeter
1964 GTO post coupe, tripower, 4speed (build)
1965 GTO 389 tripower, 4 speed, driver
1966 GTO dragcar
1966 GTO Ragtop
1969 Tempest ET clone street/strip
1969 GTO Judge RA lll, auto
1969 GTO limelight Conv. 4speed go and show (sold)
1970 GP SSJ
1970 GTO barn find..TLB…390 horse?….yeh, 390
1972 GTO 455 HO, 4 speed, (build)
1973 Grand Safari wagon, 700hp stoplight sleeper
525ci DCI & 609ci LM V head builds
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Old 01-31-2020, 02:25 PM
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How is it that 2 engines are matted together nut to butt? Is there some sort of "converter" or clutch between the 2? There is no way to get them both exact so they don't fight eachother??? How is it done..

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Old 01-31-2020, 04:30 PM
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Usually done with a double row chain coupler, same as one would couple an electric motor to a hydraulic pump. Alignment has to be very close to zero runout when aligning the couplers. Motors coupled together don't fight each other as people think they would any more than one engine having a common crankshaft.

In the early years of Go karts there were plenty of double and triple engined Go karts all coupled to a live rear axle with chain drives without any clutches, they only ran faster the more engines you added.

The unlimited pulling tractors have as many as 6 automotive engines on them all running power to the rear wheels through either gear or chain drive boxes and one common clutch.

Years ago a drag racer coupled a flathead V8 ford engine to a early chrysler hemi because that's what he had to work with. His own idea was that the the engines would be fighting one another because of the difference in power levels, he did it anyway. His account was that they didn't fight each other as long as the throttle was reasonably synchronized, and the car flew even though the engines were totally mismatched. It made no difference as the one lagging behind in power would still add to total output at the flywheel of the rear engine.

Even any engine be it 4, 6, or 8 cylinders are just single cylinders engines with a common crankshaft, the engines will make whatever power the are capable of as a single cylinder engine.

More engines, more power!!!!

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