Generation III External Engine - Truck intake plugs.

Are they removable? I mean the 8 or so ones that just look like plugs pressed into the intake. I want to add another vacuum port onto mine and that would be the cleanest way for me to do it.

Short answer= No.
Are you using the brake booster port? If not, you can remover the plug, drill it for a plastic nipple, epoxy it into the plug, reinsert it into the manifold...

Bummer. Thanks!