Here are some measurements. If you don't get what you need from this let me know. To make sure we are talking about the same thing, I am calling the "steering tube" the tube that joins the two yokes. The head stock is what I refer to the tube that is attached to the frame. Both measurements are below.
Steering tube from base of upper yoke to bottom: 8.1875 "
Length of thread from bottom of tube: 0.625 "
Head stock: 6.5"
Bearing surface to bearing surface installed in head stock (outside to outside): 6.3125"
Bearing thickness (X 2): 0.59 "
Russ