I know this has been covered quite a few times but thought I would add this for the record 59700 miles.
I replaced oil gallery gaskets a few weeks ago and here are the results :
Before oil pressure at hot idle (measured with a proper gauge) running 5w40 oil 16psi, 48psi @ 2000 rpm
After replacement running 5w30 oil at hot idle 29psi, 61psi @ 2000 rpm
I also replaced timing chain, tensioner, guides, water pump,bottom sprocket, o-rings and gaskets.
You can see the gaskets where blown out in the corners.
Drives much nicer now. Really quiet at idle, much smoother and pulls better as well probably slightly influenced by thinner oil and other parts but definitely needed doing.
Before
After