Oil pressure dropping

[carco]

OK. Pulled pan chked a rod and a main near engine front. Looked ok bit of dirt evidence. installed updated oil pump, no pressure change. Ran a couple days and pulled pan again and pulled girdle/windage tray chked rod and main near rear of engine decent. Left pan off overnight. Next AM found puddle of coolant under #3, a drop on liner bottom. Pulled head cam bearings showed copper. #3 liner cracked about 1.5 inches so inframed, w/reman head, pressure relief in filter head, dampener, new updated oil pump, first time reman injectors, counterbored block, Cummins parts. Engine much quieter and smoother one 40 mile trip at over 105K steep hills and turns, almost 800 miles on inframe.

Still shows max oil pressure of 34-35 hot and 35 max cold high idle no load at 1700rpm and 20-22 psi at hot idle.

Question???
Is there a good place to add a manual gauge permanently. Maybe access small filter head port?? or oil cooler port?? or a better access port???

Thank you!