Vac Ports ON TB TBI and carbs are Part of them and not available any other way.
Other vac ports on other thing are often same.
Vac ports that are "screwed into" intake man are mostly NPT fitting can find at many places, mostly at junk yards.
NPT is US National Pipe Threads.
Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
The Ogre's Fiero Cave