</font><font color="blue" class="small">( ...... The walls are almost 10' tall, so I can have a basement overhead door of 8'6" so my tractor can drive in and out without lowering the rops. )</font>
If it isn't too late to consider a higher door, I would reconsider the 8'6". A 10' door with the low headroom track will fit into the plans and will make your life easier should you ever get something bigger in the future, such as a small dump truck. I know, because I had a 8' door and when I did some remodeling, I changed it out for a 10' door. My garage measures 10' floor to ceiling. The larger door will not cost that much more and the framing is the same. I doubt that you will spend $200 difference between the 8'6" door and a 10' door. Go for the largest door that will fit the opening! You will never regret a larger door, but you might regret a smaller door.