cab hangs how much lower than top of frame?

[cooperhw]

Question for anybody out there with a stock square body. If you measured from the bottom of your cab near the rear body mount how much does it hang down over the cab mount? I know it "drapes" over the cab mount because you cannot see it from the side. I am just trying to figure up how much.
I should have taken some measurements in this area before I tore my 78 down.
Any help would be greatly appreciated.

P.S. or the measurement at the front cab mount might be easier. Either one will help me.