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Canadian Poncho Homepage -> Canadian Poncho -> 65-70 Full Size Power Train Tech Forum -> 67 quadrajet 4mv
Post Info TOPIC: 67 quadrajet 4mv
SGS Welding


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67 quadrajet 4mv
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Looking for an explanation 

I read online the debate about ported vacuum vs manifold for the

vacuum advance canister on my distributor.

the drivers side port on my carb SEEMS to be manifold vacuum

because when it was idling I pulled it off to check and it definitely has good 

vacuum 

car runs and works fine

i figured from everything I could find online that nipple should be ported vacuum ??

was it actually manifold vacuum on a carburetor of the 1967 vintage?

it sure seems that it is

thanks for any and all insight



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67 Parisienne Convertible 

67 Parisienne 2 Door Hardtop 
unruhjonny


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if my memory serves me, manifold vacuum is essentially full time straight from the engine;
ported vacuum is regulated via the carburetor.

Brakes use manifold vacuum, because this permits the reservoir to gain signal at any time.

Ported vacuum is essentially delayed and regulated by the carburetor.

typically the manifold vacuum is taken directly off the intake, or on a feed line at the throttle body on the carburetor;
typically a ported vacuum signal is taken off of the fuel bowl on the carburetor.


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1970 Formula 400
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1:411 1970 Firebird Formulas originally sold in Canada

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SGS Welding


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So 1967 Quadrajets do have ported vacuum?
If so what nipple?
And what was the ported vacuum operating in 1967?



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4SPEED427


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This should look just like your carb. The bottom right corner, in the picture of the carb, I put a black oval around the ported vacuum nipple where the distributor vacuum should be hooked up. 

t5.jpg



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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
SGS Welding


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Thanks Carl

Thats exactly where it is plugged in.

Basically everyone talks about the carb having a ported vacuum nipple.

I think what I have learned is that most people talk in general about Quadrajets from the 70s

with emissions provisions.This was confusing me at first.

Im pretty sure the 67 carb has no ported vacuum by design

Can you confirm?



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67 Parisienne Convertible 

67 Parisienne 2 Door Hardtop 
4SPEED427


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From what I know, that port I highlighted should be ported vacuum. However, I'm no carb expert, to say the least!

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1966 Strato Chief 2 door, 427 4 speed, 45,000 original miles 

1966 Grande Parisienne, 396 1 of 23 factory air cars (now converted to a "factory" 4 speed)
SGS Welding


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If they came ported vacuum in1967 from the factory

Then someone in the past has modified my 1967 carb to be manifold on that nipple 

Either way I am grateful that my carb is NOT ported vacuum on that particular nipple!

 



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I found this on the H. A. M. B

It kinda confirms my findings on my

67 carb.CB8570B1-C75F-499F-B2AE-02B46DFB3D29.jpeg



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