The only thing left is to seal the plug into the cover. Care has to be taken to prevent whatever you use from seeping into the vacuum port. You could use epoxy around the lip, silicone, or aviation form a gasket. Just don't let whatever you use seep under the cap.
(Since I'm going to order the brass plugs, I haven't sealed them yet. I'm leaning towards using Black silicone, the fit is so close, you would never see it, Also if for some reason in the future you want to remove the cap, it would be easier to remove then epoxy.)
Dorman plugs also come in brass, That would really look good polished on top of the polished cover.
They told me at O'Relly's they could order them for me.
They cost $1.69 eachhttp://www.oreillyauto.com/site/c/detai ... &ppt=C0332
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