Ditto- - - -that's a normal amount of pressure drop at hot idle. If you're using one of the water-thin oils like 5W-30, etc., an even greater pressure drop might be considered "normal". The whole situation hinges on how much clearance the bearings have- - - -the more clearance, the bigger the hot idle pressure loss will be. With the numbers you're reporting now, you're good to go.
Jerry
