Before making any judgments a few more details are needed....
First, what type of oil (synthetic or petroleum based) and what viscosity are you using?
Second, what are your clearances on the main and rod bearings?
The factory placement for the oil pressure sensor at the block will give the most accurate representation of the pressure the bearings are receiving. Placing sensors in the system at other positions can give various other readings.
Swithching to -8 lines won't make that big if a difference overall
First, what type of oil (synthetic or petroleum based) and what viscosity are you using?
Second, what are your clearances on the main and rod bearings?
The factory placement for the oil pressure sensor at the block will give the most accurate representation of the pressure the bearings are receiving. Placing sensors in the system at other positions can give various other readings.
Swithching to -8 lines won't make that big if a difference overall