Just for info, typically we will drop from 70 psi to 60 psi during a pass at the track. This with a vacuum pump pulling a max of around 12 in/Hg by the end of the pass from a 5 in/Hg start. Water temp also increases by around 10 - 15 degrees F. According to the racepak data.
No ill effects bearing wise and we usually run the pan as low as we dare with the oil just showing on the dipstick. Also have a Canton accumulator in there too.
I once in desperation had to go off brand choice, oil wise and ran some cheap (ish) 10/40 mineral oil rather than my usual 20/50 valvolene racing stuff. Car was noticeably quicker in the 1/4 and we ran 4 small pb's that weekend, it was the low oil pressure when hot idling that put me off from continuing to use it, 25 psi IIRC. The next race meeting we were back on the usual oil and back to the usual et's, It took a cam. intake and carb swap to best the ET's we ran that weekend.
I have run my 4.15 stroke 502 engine to 7500 with 60 PSI of oil pressure too. Mine doesn't drop however. Stays 60 PSI from the hit to the stripe. I struggled with oil control issues in the pan when I made it quicker and ended up going with the single line with the Indy swinging pickup and the Milodon flat pan (tube k-member) and that completely fixed my psi drop at launch.
