IDK how it works, and don't care.
On my streeter, I put one on,(HV) with a 7qt pan, so I could engineer more oil to the top end to protect my expensive valve gear, and to cool my valve springs at 7200rpm. It seems to have worked cuz the engine has accumulated over 100,000 miles on it since year 1999 with no top-end failures.
I have no clue about my oil-pressure, cuz I run the slow-to-respond stock 1969 factory un-calibrated gauge, which I never look at anyhow. The way I see it, if something happens at 7200, that's 120 revolutions per second, so even if I had the oilpressure gauge wired to my brain, and even if I could respond instantly, the engine would be cooked before it stopped spinning of it's own inertia. So I hardly ever almost never look at that gauge.
But one thing I can tell you is this;
the first time I revved it up, this engine blew oil out onto the passenger side header, which I traced to the oilfilter plate. This, after I ported the internal oil-passages and enlarged the oilfeeds to all the bearings, and supplied extra oil to the top-end, and with the same 15W40 oil, that I had always used, with never before having this issue. I doubled up that plate,drilled 4 more holes in it, and enlarged the hole up the center of the filter retainer, and switched to 10W30,and that was that.
How many stock engines have ever had this problem.
Ok so, at that time, I was running a Hughes HE2430AL, and somebody is gonna ask why I would spin that 360 all the way to 7200, when clearly the power of that cam peaks around 5200. And the answer is; cuz I can. It's a streeter. And I like the sound of twin 3" full-length trumpets screaming like banshees, drowning out the screaming tires; from zero to 60, for 5 to 6 seconds atta time. If your engine could do this, you would wind her up too. It's extremely addictive. Well to me anyway.
So for me, the HV pump is really cheap insurance.