oil pressure

I had a similar problem with my 367 but with a twist; at high rpm I would get a lotta smoke from under the hood which I traced to oil dripping onto the header. Thinking the filter was crap, I replaced it with another brand. And another;with no change. Since I love to hear that little 6.0 singing to 7000, this had to stop. So, I drilled four more holes in the filterplate,reamed out the attaching fitting,and chamfered it all.That solved the leakage. But I also switched to 10W30 soon afterwards.
I can't tell you the operating pressures cuz I don't have a gauge. No joke. Just the factory rally gauge. That was about 80,000 miles ago, perhaps 2002
I don't know if this helps cuz I'm not near your power level.