They were heavily pitted on my 1966 also. I just sand blasted them, and filled in the pits with brass. The chucked each one up in the lathe and made semi-round once again. On the project it saved me about $30 at the time, which is why I did it.
How long will they last?
I dunno, for did it fifteen years ago, and they are still in place, but the ball joints got replaced ten years ago too.