I’ve been looking for parts to rebuild the front end of my ‘72 Runabout, and finally found the spindles (4 lug) at Auto Zone’s website.  They also had the lower ball joints which are tough to find.  The upper ball joints are available from a lot of places, but this is the only place I’ve found that has the lower ball joints.  They list them as a rare part and they aren’t cheap, but they have them.  Hope this helps someone.