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Info needed for 17059547

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oktorque:
I wonder if anyone could please explain the primary enrichment tubes, what they do and how they do it?

Also, does anyone know the aprox. cfm of the primary side of an 800 QJ?

Thank you.

firefox3:
What are primary enrichment tubes??

The small main air bleeds allowed the use of relatively small 67 jets. I would leave the air bleeds alone and maybe go up one or two jet sizes with your 45P rods. Then you should have some idea where your calibration is by driving it. I would "lock" out the secondaries so you can focus just on the primaries.

I don't think anybody on here can tell you exactly what jet/rod/air bleed combination you're going to need with your Ford 300. In the world of carburetor tuning, there's almost always some trial-n-error involved.

oktorque:
I found the info I needed.  I had to go back and read a bit in Cliff's book.  The primary enrichment tubes, it seems, act as an accelerator pump so the engine does not go lean the instant the secondaries are opening.


INTERESTING INFO:  I dug around on the web and found flow test results for the primary side of some pontiac QJ's. 

Primary cfm for a 750 QJ, varying slightly from model to model, is ABOUT 180 CFM.

PRIMARY SIDE CFM for an 800 cfm QJ is about 210 cfm.

oktorque:

--- Quote from: firefox3 on August 01, 2014, 08:08:33 PM ---What are primary enrichment tubes??

The small main air bleeds allowed the use of relatively small 67 jets. I would leave the air bleeds alone and maybe go up one or two jet sizes with your 45P rods. Then you should have some idea where your calibration is by driving it. I would "lock" out the secondaries so you can focus just on the primaries.

I don't think anybody on here can tell you exactly what jet/rod/air bleed combination you're going to need with your Ford 300. In the world of carburetor tuning, there's almost always some trial-n-error involved.

--- End quote ---

Thanks.  I know this carb is set up for a 231 turbo in a regal.  Since mine is for a truck, pushing more weight, with a larger engine, I know I'll have to go up a bit with the jets or down with rods.  We'll see. thx k

oktorque:
When you decode a serial number how do you further define what engine the QJ came on.  For example, the serial # on my carb tells me it was on a Buick.  Is there a source that tells you which model Buick that carb was on?  Does anyone know? 

Thank you.

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