Low oil pressure 5.7 hemi issue
 

Hello, I have a Chrysler 300C 5.7 HEMI made in 2005.
The previous owner changed oil every 15000 miles therefore the crankshaft broke.
I removed the engine and replaced the crankshaft, crankshaft bearings and con rod bearings. 1500 miles later I started the car in the morning and the engine started knocking at valve lifters so I started oil pressure measurement and it was 80% lower. I ordered a completely new oil pump. It stayed the same after replacing the oil pump the pressure is still 80% lower than normal.
What could cause this?
I am thinking whether it can be bad camshaft bearings or a broken valve lifter around which the oil pressure could escape?
Or some other oil pressure valve besides the oil pump?