oil pressure dropped to 0 and we replaced the oil pump, oil filter, and of course put all new oil in but after all that work it still is not reading and it ticks. Any ideas?

New oil pick up tube??... Checked actual pressure with a test gauge???

Does the oil pressure ever come up and have you been driving it? How loud is the ticking? Did you put a manual test gauge on it to see what the actual pressure is? Did you check the bearings while changing the oil pump? Could have a valve train problem, lifter out of bore, cam plug, cam bearings?