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Discussion Starter #1
Hi All,

I have a holley 650 dp that has no vacuum ports. I drilled a 1 inch spacer and press fit the ports that I need. It works great, except now I can only run a 2.5 inch airfilter cartrige on a drop aircleaner. I think the top of the aircleaner should be higher than it is. Has anyone drilled and tapped holes into a dual plane rpm? I need a port for my dist. one for brakes, and one for pcv. Would I drill them on the short runner side or the long runner side, or should I drill them right at the divider?? Thanks for your thoughts.

Dan
 

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Are you sure your Holley 650DP has no vac ports? Not that I'm doubting you, but I find that very odd. Mine has a big one on the base plate exiting straight to the rear under the rear float bowl, and a small one on the base plate on the passenger side front, plus a ported outlet in the front metering block. List 4777-2.

For your Perf RPM, there should be a tapped hole on one of the port runners that would be on the back side of the manif and sit under the rear float bowl. Edelbrock makes a low profile 90* vacuum fitting that allows you to use this port without a carb spacer. Edelbrock part # is 8096.

I think if I were going to drill and tap the manifold for a vac fitting, I'd me most inclined to drill below the carb mounting flange into the plenum on the rear side. But I've never actually done it.

For my power brakes, I used the big port on the back of the Holley. I "teed" into that line and used that for my PCV. Somebody told me that wasn't the greatest idea, but honestly, it works fine and I've had no problems.
 

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Discussion Starter #3
The 650 is from the HP series and has no ports on it at all.

That is a good idea for the brakes. My PCV is in the front so I would need to drill one there and one smaller hole at the back for my vac advance.

I think this will require more thought.

thanks BPOS for your comments.

d
 
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