6.4L engine oil pressure

50 is a little thick for that engine. drop it back down to 5w20 if warmer climate but not no 5w50. 0w is for colder weather 5w is fine for most climates but canada.
the 50 is for loose clearances like old school engines. a 6.4 wont like it and eat crap up quickly or wash the bearings out of it cuz it cant escape.