not quite sure what you mean but ill guess, measure from the bottom of your tire(basically the ground) to the top of the wheel well opening above the tire on at all four wheels take the measurement of all four then after you lower it do it again and compare ,then whala your total drop ,make sure your on a level surface for all the measuring to be acurate,
i see in your sig its says 4/5 so if your already lowered you should be about 4/5 lower than stock cause the parts are pretty acurate
my front is 24.5"
and 27" out back
the reason why i asked this question was because the rear didnt look like 5".
i was told they gave me blazer 2" leaves instead of 2" p/u leaves
so my truck didnt sit so low. it looks more like 4" out back
i hope you understand what i wrote
i just gotta get a new pair of 2" leaves
thank for the help though