Series 60 oil pressure

Ok my oil pressure over 2 years have been gradually going down from 35 at idle to 25 and 50 down the road. So i decided to do my main and rods the engine has 1.3 million never been opened. Rods ware surprisingly in decent condition only one rod upper bearing had a small spot where you can see Cooper rest has some flaking other then that engine looked really clean. I did my own rods and mains so i know it was done right my oil pressure stayed the same no change at all. After week of running i will be dropping oil pan just to recheck torque specs on rods and main for safety reasons but while i am there i will be replacing relief and regulator valves on the oil pump to see if that does anything any other suggestions while pan is off? Or should i just go ahead and replace the oil pump

The head was checked when i did my cam seals and everything looked good overhead done 75k ago

 

My replies didn't post for some reason.

I dont think its fuel dilution as the pressure stays consistent from fresh oil change to when its time to change again.i would think if it was fuel in oil pressure should then start dropping as miles rack up.

I did not check with manual guage yet but i am going to i am looking for a shop to rebuild my pump today as the pump is original i am sure its worn yo some degree

 

Update pressure fixed took pump off cleaned it changed all seals istalled new valves and boom 55 idle cold 35 hot and 30 after pulling a hill temp 215 fan on idle im very happy



I wrote a reply before this but it did not post anyways thank you all

Best thing is 55psi at 1400rpm cruising down the hwy