Roger that. The oil filter and adapters and lines can only reduce pressure with any added restrictions. Check the clearance between rockers and shafts; should be .001-.003"
BTW, stock pump spec pressure is 45-65 psi at 1000 rpm and a minimum of 20 psi at 500 rpm. Numbers are for 10W30 for most climates, or 20W40 for hot climates. The Melling oil pumps' pressure relief springs are reportedly stronger per KrazyKuda's data, for both HV and standard oil pumps. Did you install a new pump and is it a Melling? We put in a Mopar Performance HV pump and it is actually a Melling, and has the higher pressure spring.