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Discussion Starter · #1 ·
I recently bought a new 4 barrel carburetor and intake and my problem is my old 2 had a factory spacer that had a vacuum port behind it. Does anyone know what this port feeds air to?
 

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If its a 3/8 port, probably PCV.
 

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Discussion Starter · #3 ·
Will i get away with not using a similar factory spacer with this new carb? The carb has a PCV port already on it so it would be redundant im assuming to have two PCV ports.
 

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I recently bought a new 4 barrel carburetor and intake and my problem is my old 2 had a factory spacer that had a vacuum port behind it. Does anyone know what this port feeds air to?
Yes as stated below it is the pvc outlet. Get you another spacer for 4 carb same way and run a rubber hose to the val cover .
I run mine to the headers and a different pipe instead of rubber but that will work. You could do without it if spacer set carb too high to hit your hood but add it back if possible.
It allows pressure from motor to come out and return back or so I suppose. Someone will give you more in depth info soon.
 

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Will i get away with not using a similar factory spacer with this new carb? The carb has a PCV port already on it so it would be redundant im assuming to have two PCV ports.
Sorry I was typing as you were.Yes that one on carb will be fine , do without the spacer. If you run a race car sometimes a spacer will add a touch of more power
 

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Discussion Starter · #6 ·
Sorry I was typing as you were.Yes that one on carb will be fine , do without the spacer. If you run a race car sometimes a spacer will add a touch of more power
Thanks for the response. I'll be installing the new intake and carb tomorrow so if it doesnt run properly i guess i'll know why.
 

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Thanks for the response. I'll be installing the new intake and carb tomorrow so if it doesnt run properly i guess i'll know why.
Make sure you use correct intake gasket and not close any holes up. It is easy to do with wrong gasket set. I bought a 427 stroker chebby roller motor built from a speed shop I know nothing about. My speed shop tore that motor down. Other speed shop placed wrong head and intake gaskets on , was cutting power down.
 

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Discussion Starter · #8 ·
Make sure you use correct intake gasket and not close any holes up. It is easy to do with wrong gasket set. I bought a 427 stroker chebby roller motor built from a speed shop I know nothing about. My speed shop tore that motor down. Other speed shop placed wrong head and intake gaskets on , was cutting power down.
I appreciate the advice, yes ive already purchased the correct gaskets and i'll double check when i tear the top end down tomorrow.
 

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The functions of a spacer are to increase the plenum volume (not necessarily desirable on an aftermarket manifold) and to cool the carburetor/gasolene a bit. And the vacuum fitting on the back can be replaced with any other source of manifold vacuum on the carb or the manifold.

I read a great article on this on the Car Craft web site a year ago or so. It's worth digging up if you want to know when to use a spacer.
 

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Sorry I was typing as you were.Yes that one on carb will be fine , do without the spacer. If you run a race car sometimes a spacer will add a touch of more power
Guess I wasted my money on a spacer since Im not sitting in a race car.

Spacers have their purpose, and his combo could very well benefit from one.
 

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spacers , never know if add , lose or the same till they are tried . testing is the only way
 

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I presume we are talking a divided dual-plane performance manifold? While there are a bunch of factors that make a difference, generally a 4-hole spacer can help low-end and open plenum spacer for higher rpms. The 4-hole tends to not affect higher rpms too much, but the open spacer tends to kill the lows as it removes some function of the divided dual-plane manifold. So, spacers can be used to tweak the manifold power band a bit on the pavement. Be careful of dyno results, as dyno's behave differently with spacers. More spacer almost always gives more HP. Not generally so on the street or track. Unless designed to use one, the manifold should be used as-is and tested for changes with spacers from there for best overall performance.

David
 
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