Black listed

I would make sure it's not exaust leak it will fool you if not then maybe one of the rocket arms is warring out or a lifter is starting to colaps even my brand new engine in my Dakota starts out with high oil pressure and goes down when warm . I thank that oil your running is to thick I,would run 10w30 or 10w 40

just had exhaust done all brand new i ran the thicker oil because my dad and a few people i talked to on here have done it with higher mileage motors. this 360 was put in buy old owner and done horribly wrong. was suppose to have been rebuilt mild cam rofl. anyway you can check the build if you want dont wana post to much on anothers thread lol