Keeping in mind that there is a slight dip in the middle, the middle measures 7.5 inches and on each side of that it is roughly 8.25 inches from the roll bar frame to the top.
I'm curious as to why you need to measure out the size? They only come in two flavors. 986 and 987. 986 has that dip in the middle to clear the top's locking mechanism. The 987 is straight across.