Oil + additive viscosity

Before I start the temp gauge is water temp.
Just a thought I have in mind. Here in oz I have to run a remote oil filter. The factory setup was a cast plate over the block where the filter originally screws on and pipe fittings attached to the plate. There was an oil filter bracket fitted on top just next to the distributor it was bolted to the factory cast intake manifold. The pipes were 1/2" steel which connected between the filter bracket and the block. My setup is almost identical where I have utilised the same factory filter bracket. Since I have an edelbrock LD4B manifold I relocated the filter bracket on the drivers side guard. I have made up braided hoses to run between the block and oil filter. These lines are no more than a yard in length each. I used Speedflow hoses which are locally made and their matching fittings to suit. The I/D of the hoses I used is 7/16". Since the oil filter is straight after the pump and before the oil gauge could this pose a restriction? Saying this inside the filter bracket the centre thread which oil flows through it there is a one way valve which has an orifice of 7.5 to 8 mm diameter. Thats about 5/16". Could this be the problem why the oil pressure is dropping at higher rpm?
Regards
Billy D...