Oil Pressure Dropped...

Odd that I saw this post, as I was just going to post something similar.

My engine is a few years old, has maybe 2000 miles on. Car runs great, starts easy, etc.

It always ran higher oil pressure also (70-ish @ 2000rpms hot). Recently I changed to a 10w-30 from 10w-40 oil, and also put in roller rockers (had non-adjustables). Now it's only running about 40psi....ever. Even at 3-4,000 rpms it stays at 40psi...I have a stock pan with a windage tray welded in it.