408 oil pressure issues

I steer clear of Fram filters. I try using Purolator most of the time as I have comfortably put like 100,000 miles on their filters in the last 6 years across my drivers. Thanks for making sure to add that point to the list, as I want to be sure I am not leaving anything out. As stated, warmed up I get down to about 10psi at idle and it will pick up in throttle but not above 45psi. Also of note, the oil pan is the stock 360 C body oil pan that I have used since we put the 360 in it over 10 years ago- no windage tray and a stock replacement pickup.