Low Oil pressure

Gooday from down under
Long time reader first time poster

I am having a problem with my recently rebuilt 318 la oil pressure staying low
After running in the cam in, i noticed the oil light flickering on at idle, Fitted a gauge to reveal
about 18psi cold & 10psi hot at idle & a maximum of 35psi at revs ( will not go higher).
After reading many posts i changed to 50 grade oil & very slight improvement but not fixed,
checked with another gauge , same, Changed oil filter & inspected inside no metal same oil pressure, checked rear plug , & its in , checked rear cap plug down the oil pressure hole & its there as well.

Bored .030 new mains & big ends fitted ,
small summit cam kit, with can tensioner fitted
original cam bearings & oil pump were used after inspections
plastigauged mains & bigends & all were within specs.

I am thinking the valve relief is set way too low or partialy unsealed or perhaps
the cam tensioner plate not sealing the oil shafts,

Any thoughts welcomed

cheers pete