Rule of thumb is 10 psi for every 1,000rpm. If you are turnig over 6,000 and your max pressure is 55 you are running on the low side. Try going to a straight grade 40 race
oil that should help some.
If you look at the Melling link that someone put up it shows all the miths about HV/HP pumps. Most folks that tell you the kinds of things you have heard are not as smart as they think they are. We use the HV/HP pumps in all of our performance engines and have never had a problem and I have built a lot of engines in 20+ years.