This unit is in excellent shape. The 2-3/16 x 10 threads are looking great also. The 6 bolt pattern is 133.4 mm or 5.250 center to center measurement. You will need your own 2-3/16 x 10 thread Nut. We also have another unit like this, but the A2-8 Mount.
Please make sure this is correct for you. Most same units like this for sale have bad Shape Threads, not this one. These are Great(look at all the pictures). Spindle Nose Threads: 2-3/16-10 TPI.Flange Outside Diameter: 6.45. Overall Length or Depth of unit: 5.050.