Nothing really confusing about it. As the statement says: a stock pump, even at high revs, will keep the engine oiled. A high volume pump is just that: it pulls oil out of the pan in a high volume. What the statement is saying, is depending on bearing clearances, pan volume, oil passage sizes, it can actually suck the pan dry of oil. Add into that, the windage from the crank (if you're not using a windage tray, always recommended) and a pan without baffles in it, too keep the oil near the pick up screen under exceleration and cornering, you could actually starve your engine for oil, even with six or seven quarts in it.
The way the big blocks are designed, the windage, the centripetal force of the crank turning under high rev, can actually pick up and hold eight quarts of oil wrapped around the crank, starving the rest of the engine. Hence the reason a windage tray is never a bad idea. The tray breaks this suction from the rotating mass and keeps the oil where it should be: in the pan.
Now add into that a pump that wants to suck the pan dry at a high rate of speed...kaboom!
Unless you're looking at revving the engine above 6500-7000rpm I'd say the stock pump will work fine, depending on the bearing clearances.
A high pressure pump can make up for loose clearances if you're running things a little on the loose side.
You need to know what bearing clearances you have when you make your selection. Are you running factory spec clearances? If so, and you plan on keeping it within the rpm above, then the factory pump should work fine. If you're running things a little loose, you can think about a high pressure pump. If you're thinking of running a large capacity pan, with tight clearances you can think about the high volume.
The pan, in my opinion, is always a no-brainer if you're running a street car. Get the Hemi pan. Larger by one quart with the baffles built in. Usually a little cheaper than the "aftermarket" pans. And now is definately the time to think windage tray. Cheap insurance. Especially with the big block; it's an easy bolt in. Chrysler installed them factory on a lot of big blocks.
But what are your intentions with the car? Street/some strip? Street only? Strip only?
