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Double Pumper or Vacuum Secondary?

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Old 08-01-2003, 04:02 AM
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blackbirdpilot
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Default Double Pumper or Vacuum Secondary?

My '69 has a 650 Double pumper, manual choke, mechanical secondary. I want to use a stock aircleaner, but the breather vent to the pass side valve cover hits the secondary accel pump. I like the idea of the double pumper, but not sure If I will benifit from it.

Is there a way I can modify the carb, or the air cleaner (not to much) :thumbs: to make it work with the double pumper? Should I just unload the double pumper and go with a vacuum secondary?

Opinions? Pro's / Con's?

Thanks!:)
Old 08-01-2003, 04:30 AM
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marky mark
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Default Re: Double Pumper or Vacuum Secondary? (blackbirdpilot)

I ran into this when I switched to tall valve covers. Mine was a Quadrajet but the concept is the same. My problem was that I no longer could use the air cleaner conection to the valve cover as it was in a much higher location.

Solution is to have the tube on the bottom of the air cleaner base cut off high enough to clear the carb. Then from the top side of the aircleaner have a "cap" welded on to the opening where the spark arrestor attaches which will seal off the air cleaner from allowing dirt in (from the bottom).

Then get a breather cap with grommet that fits your valve cover. That now becomes your engines sourch for air flow. Worked for me. Only down side was I had alter to air cleaner base. But they aren't terribly expensive if you wanted to someday go back to using the original style.

There are some cool looking caps from Billet Industries I believe (Jegs/Summit carry them). Check them out.

Don't think there is anything wrong with this conversion. Others may not agree.

Regards, Mark :flag :chevy



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