FLOW not pressure. That's what's important. Never heard of anyone sucking a pan dry with a HV pump.

I run a HV pump, with a stock pan, windage tray and crank scraper, on my 306. I also run an ARP pump driveshaft as this is a notorious weak link in a SBF at high RPM's anyway, HV or not.

I have 50 psi cold, 40 psi hot at idle.

I broke the engine in with 15W40 diesel oil, and will be switching to a 0W30 synthetic real soon. That should help with any drainback issues (if there even is one) as well.

My 0.02