If the seals say national they have been replaced before. Hit the books for current numbers. There may be sealed bearings that will work, but today's seals are much better than they were 50 years ago, and the original design generally works.

Devin

If you can't hose it out it ain't a truck

55 3100
63 Corvair Monza
64 El Camino
72 240Z
01 Suburban