Sorry I wasnt clear on my last post (at least I think I wasn't). I am talking about the vacuum lines that attach to the various locking and airflow actuators in the interior of the car. I believe they are supplied with a vacuum from a pump inside the car, and not directly from the engine. Most of them have plastic connectors on the end, and I dont think a golf tee will work (unless I remove all the plastic connectors). I was wondering if having these lines disconnected might damage the pump, as I understand they are very expensive.
Oh, and I did use new O-rings for the heater core. Funny, the heater core must have had a re-design, as the new one has a separate inlet at the top, but it came with a metal plug to seal the hole. Took me a few minutes to find the plug though, so I thought they had sent the wrong one.