Thanks so much for your reply. You absolutely pounded the nail! Although I was getting some vacuum through, the white plastic orifice coming out of the vacuum pump was nearly completely blocked.
Should I be able to put a straightened paper clip all the way through this orifice? I got it cleaned out enough to cure my hard shift blues but I'm wondering if I still have a partial blockage.
Thanks again for taking the time to help us DYIers with our old cars. They are a lot of fun to work on, especially when the results are so dramatic.