Go to
www.rockauto.com to save significantly on the u-joints. Search by part number.
Or you can go to Auto Zone and get PDQ1-0005 u-joints. These are Neapco u-joints with the grease zerk on the end cap and beefier to boot. They will only run you $15 a piece.
If you go to discoweb and do a search on the this oft repeated topic you will find the Neapco part number for the centering kit.