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Discussion Starter #1
I have a 66 269 auto.I just installed a Holley 600cfm 4bbl carb, using an adaper plate for my 2v intake manifold. I have not noticed much increase in power, but now I hear a load air noise coming from the engine. It like air being sucked through a straw. Any Idea what this is and how to trouble shoot this problem.
 

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You probably have a vacuum leak, but either way that carb is pointless on that intake.


Frankly I'd run an autolite 2bbl carb until you can afford even a stock cast iron 4bbl intake.
 

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Discussion Starter #3
This is a rebuilt carb, with an 3 to 4 adapter. Any suggestions for diagnosing the leak. What intake would you reccommend.
 

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I would recommend an Edelbrock Performer. Kinda funny, "like air being sucked through a straw", is sort of what you're asking that carb to do on that manifold. Switching to a 4v intake like a Performer should start showing an increase in power, but it may start you down the road of "I want more!". Next thing you'll be wanting headers, a bigger cam, aluminum heads,..... It's contagious.
 

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You may try taking a piece of hose 3/8 -1/2 or so. Put one side to your ear and probe with the other end. It will lead you right to the leak.
 
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