I have 700 miles on the rebuild of a 440. Oil pressure has been fine at about 60/65 on the highway. Yesterday was a 100 degree day. Water temp was 3/4 on the gage up from the usual 1/2 way point. I could see the oil pressure drop as the temp went up. It went to 45 at 70mph. Idle was still around 15. I use 20/50 VR1. I think this is a bearing clearance issue and no change to the pressure relief valve setting will really alter things, right?