Did you try to put a spin-on or full flow filter on instead of a bypass filter and leave out the restrictor oriface? If you left the oiling system stock plug off the filter holes with bolts and see if that fixes it, if so, add a restrictor on the outlet of the oil filter. It just drains back into the pan.

Paint & Body Shop moderator
A lone amateur built the Ark. A large group of professionals built the Titanic.