Good question.
I have been wondering what the factory height was as well.
It would be nice to know if my fender is 1,2, or 3 inches lower than it was new, so I could judge the amount my vehicle will raise with a new suspension.
If it is down 3 and I put in a 6 inch lift, will I see a 9" difference kind of thing.
Maybe someone has an old moog spring book that shows how to measure the Bronco so we could compare. The moog books used to show height range and measuring points, but I haven't seen one in 15 years.
Jeff