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Old 04-29-2004, 10:23 PM
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Manifold Vaccum line

I have a mild chevy 350 and it has a 450 rochester quadrajet right now. I have a Dual plane, Performer intake manifold and I want to slap a 600 holley, double pumper carb on it but the vaccum on the manifold for the transmission is in the way. Is there anyway I can make something or buy something so it will clear??? Any help is appreciated. Thanks

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Old 04-29-2004, 10:40 PM
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In some cases you have to use a carb spacer (4 hole perferred) or you can stack gaskets providing you sealant them together with a light coat of sealant, you can also look for a lower vacuum bung off other intakes. also check yours and see if it can be threaded further in. I doubt you`ll see much performance improvement by going to the Holley, if there`s any at all, but you will notice a MPG difference, and it won`t be for the better.
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Old 04-29-2004, 10:43 PM
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The easiest way to do this is to remove the fitting in the rear of the manifold and install an allen pipe plug. It will sit flush with the manifold and not get in the way of the Holly.
To get vacuum to the transmission use one of the vacuum ports coming off the base of the Holly. When you start the engine find the fitting that has manifold vacuum at idle and no vacuum when you rev-up the engine. You may have to add some hose to the steel line to reach the new port but when you get that hooked up you will be good to go.

Have Fun
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Old 04-30-2004, 05:10 AM
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450 Q-jet, doesn't exist, the 4G came in 485,550 and690, your carb should be 750 cfm, 1-3/32 primaries!
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