I just had my 2003 5.3L engine apart to repair oil leaks, while in there I replaced the oil pick up tube oring and installed a higher pressure spring into my oil pump relief. I have a Wix filter on the truck now. Oil pressure is 65 psi HOT at idle and 75 PSI HOT driving.
I have only seen a 5 psi drop between oil filters when using the Hastings brand filters but they tell you.upfront this will happen due to extra filtration.
I fixed a 6.2L with low oil pressure a year ago, it had 175,000 miles on it. Installed a new O ring on the pick up tube and added a spacer to add pressure to the oil pump relief spring. It had 35 psi at hot idle and 45 psi driving after the repair. You might also consider the Melling high volume oil pump since you are at 200,000 miles.
Best to fix it before damage happens.
Sidenote: I took apart a 5.3L that I had installed a new Melling Oring on the pick up tube just 30,000 miles ago. That O ring was hard and flat already after only 30K and the pick up dropped right out of the pump on tear down. You should have to pull it out. On install this time I chose to use a Fel Pro O Ring for the pick up tube it went in tight, I hope it hold up with time. If over 100,000 miles the factory o ring is suspect and fails commonly.
Your oil pan also has a secondary oil pressure relief that is supposed to limit oil pressure to 65 psi max, if that fails you can lose oil pressure. If the oil pan comes off it should be replaced with a new pressure relief valve. It is inside the pan close to the oil filter location.
