Get a big pry bar, and a block of wood or two. Put the pry bar under the edge of the distributor, and using the blocks of wood as a fulcrum point, start pushing down, and watch the distributor pop up. The distributor on my 1969 Miller Meteor Cadillac was stuck just like yours, and that is what Ed did to get it out. I would clean up the old one and put some new old stock points back into it, and continue to use it. The problem with the rebuilds is that they are made up of lots of miscellaneous parts from other distributors, and the advance weights might not be proper for your car. This can lead to all sorts of ignition problems.
The distributor in my 1963 Chrysler failed on the road, and a rebuilt was all that I could get. I still have the old one, and some day, I intend to rebuild it and put it back in.