Wild guess: if you raise it 4" and then add 1.5" of the height from the tire (3" in total = 1.5" per side of the rim), that adds up to 5.5" total.
It will, as I understood, sag a bit, or it will be higher in the start so it will sag to 4".
Anyhow, you can count with 5.5", with an inch more or less.
I just rearched my springs to factory + 1" and put the "alleged" 31s and the only way I can enter my garage now is topless. The Bestop's horizontal bar is too high for the garage door, as is my hard top.
Beauty is in the eye of the beer holder
* 1994 ZJ (by VIN) with a 1995 engine (PO knows why)