Nozzle hitting Z end-stop

When doing a Z endstop calibration on my 500, the bed isnt moving down far enough to clear the endstop. When the nozzle moves right from above the VAOC camera its impacting the end-stop.

I am running a nozzle camera on T0, and using the modified taller printed VAOC camera enclosure. It seems its just missing a proper Z hop height. but I cant find where this variable is defined