50-80 psi at cruise (3500 rpm) is not unusual for these motors. With cold oil on cold startup you can get well over 100 psi. My 100 pound guage was always pegged on startup. Idle should be at least 15-20 or so, but down to 10 is normal.
The turbo taking oil from the filter housing will see nearly the same pressure you see on the guage. Pressure at the head will be much lower, hence the reason people with BB turbos use a head feed. Scotsee may have been refering to BB turbos with the 50 psi figure.