The whole front crossmember from '63 through'87 just unbolts, (may have to drill some rivets on some.) What the folks wanting 6 lug disks do is to have to rotors redrilled. '63 - '70 are 6 lug drums, '71 - '87 are 5 on 5 disks. '73 on the the ball joints and tierod ends are a bit heavier and won't fit the earlier stuff, and they're cheaper, too. More demand I guess. I hope this helps.
Les
