Popping noise in the front end

It could be anything from a bad ball joint, steering box, tire rod binding. If you are setting still and rock the wheel does it pop? Does it matter which direction you turn? Do you have to be moving to make it pop? What parts were installed for the drop? 6.5 is a tall drop and should have had pieces to drop the transfer case, steering, A-arm cradle and more.
I would have the place that installed it check it over as it could be something simple like a loose bolt, or it could be that the lift is causing the axles to pop and damaging them and the differential.