Adjusting Oil Pressure

[Ct54531@aol.com]

Am I correct in thinking that I can adjust the oil pressure in my 65 4A using 
the relief valve? If so, what is the procedure? 
Once the engine is hot, at speed the pressure is, at best, perhaps 30 and at 
idle is barely 10. 
Do I loosen what I assume is a retaining nut (topmost and smaller of the two 
on the valve) and then turn the large screw? Which direction?
Should it be done with the engine running so one can visually check the gauge 
i.e.- is the adjustment readily apparent?
Thanks.

Jim
654A