The older Big Twins with the larger key torque the flywheel nut to 60 to 65 Foot pounds of torque. The newer Big Twins with the smaller woodruff key have a slightly different taper in the hub and rely on the taper to grip the crank more securely. These require 100 to 105 foot pounds of torque. Lapping them together will even the taper and make them less secure. If you MUST lap them, try to take more material out of the upper part of the taper . . . 🙄
