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Discussion Starter #1
I'm installing an Edelbrock top end kit on our 1968 289 Convertible. The manifold is Edlebrock's 289 Performer manifold. With this setup and Scott Drakes 4 barrel spacer with PCV port, the stock hood still closes with the original air cleaner in place - but just barely.
I'd like to use the PCV port on the back of that carb spacer, but I'm not sure if that spacer will pick up sufficient vacuum from that manifold. Has anyone used this setup?
 

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Does your Edelbrock "top end" kit include an Edelbrock carb? If not, what carb are you running? The SD spacer should work fine if you require one and you won't have to worry about the Performer manifold providing sufficient vacuum.
 

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Don't really follow you... the amount of manifold vacuum isn't going to be dependent on the intake manifold but, rather, the camshaft profile, cylinder volume and compression ratio. The ideal point for obtaining high vacuum for the PCV is right below the throttle plates so the spacer should be just about ideal.
 

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Discussion Starter #4
UPDATE: The Drake PCV spacer and the Edelbrock 289 Performer manifold are not compatible. I bet some folks on here could say why, but I can only guess the dual plane manifold doesn't work the way the factory manifold does. This drove me crazy for about a week. I actually pulled the timing chain cover back off of the engine to check the cam timing - since I had just installed a new cam. It was fine. I could not get the engine to run other than to crank it over with about 1/2 throttle. Then it would eventually fire, rev up very quickly and die as soon as I let off the gas. It acted like it had a huge vacuum leak. I swapped the Drake spacer for a 3/8" thick fiber spacer and it solved the problem.
 

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I was surprised to hear your issue with the two components. It sparked my curiosity so I went to Summit Racing's website and searched the spacer. The image below is what I found and is consistent with what I understood. As long as you had good gaskets on both sides of the spacer, I don't know where it could have been faulty. Is this the same part number as the spacer you purchased? Is the bottom of the casting open?
 

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The big open hole in the top of the Edelbrock 289 Performer manifold is not compatible with the open-bottom stock 4V spacer. You'll have to use the integral PCV port on the carburetor.

 

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Is the part in the second picture a thin rigid spacer? It doesn't look like a gasket. I superimposed the bottom of your SD spacer (pic #1) onto it (pic #2) and it appears to seal. If it is in fact rigid, wouldn't it require a regular carb base gasket on either side? It also appears from the patterns left in the components, that you were running it between the spacer and the carb. Is it possible to install it between the manifold and the spacer?
 

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Discussion Starter #9
22GT - thanks for the confirmation. I knew I wasn't crazy - ok, I was pretty sure.

Rhut - the 3/8 spacer is a soft spacer - no gaskets required - so I ran it by itself. I just ran the Drake PCV spacer with just the 2 gaskets
 
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