Metal in the Oil

[Adger Smith]

It is not a concern because the hole size in the front galley only feeds the front main and one rod journal. The same sized hole in the middle 3 feeds their respective main journal and 2 rod journals. The rear galley, like the front, feeds only one main and one rod journal. You would have to drill a Huge hole to draw away the same volume of oil from the front to match what is taken away from the middle 3. You are dealing with a passage (a branch of the oil system) that is the same size as the others, but is only required to flow 1/2 the volume of oil. Don't get oil volume and pressure confused. They are two different things, yet pressure is dependent on available and required volume. Required volume is dependent on width of journals, diameter and clearances in the engine (or simply oil system leakage). Availavble volume is determined by the pump type, size and rotation speed. In a system without a bypass, after the required system volume is reached, the more rpm you spin the pump it will just keep increasing pressure. (that is why we use a pump with a bypass) Simply stated all pressure is is resistance to flow.
Do it, the front cam bearing, rod and main will never know you modified the system. The timing chain, and front of the block and timing gear bearing will know you did it and they will be happy. :~)
Check that chain tension!!! It was probably so tight there was no clearance to build an oil wedge in that bearing. I liked that idea that was posted about drilling the bearing to provide a little oil on the leading side to build an oil wedge.