Newbie here but been lurking a long time. Can someone tell me the purpose of the hole in the intake. It is directly below the carb, a one bbl holley. Is it connected somehow to the egr, and do I need to plug it if I use an egr block off plate?

Yes.
No.

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Casually looking for a Clifford hyperpak intake for cheap.

Thank you. So I don’t need to fill that hole. Thought I read a post somewhere that said it needed to be closed off if egr was removed and a block off plate installed. Maybe I just misread or misunderstood.

Some folks have been known to tap that hole for a pipe plug. I think the worry is that with a block off plate, if you don't get it sealed around the EGR intake port, you could have a lean condition. With the pipe plug in the bottom of the plenum, there's no worry about that. Cut yourself a gasket for your plate, bolt it on, and go.

Roger

I tapped that hole for the power brake booster, but all you really need to do to disable the EGR is flip it around 180 degrees.

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If it was easy, everybody would be doing it.

I did tap the hole below the carb on my super 6 manifold, but when I got in there I discovered that there were already 3/8 NPT threads under the diamond hard carbon buildup that filled in the threads. I had to Dremel out some of that carbon to give the tap a place to dig in and start.
I used plenty of red loctite on the plug that I used. And I'm still gonna put a block off plate on the edge of the manifold.