I'm seeing about 55 psi hot idle (1200 rpm) and 75-80 psi at speed. Another 10 psi cold.

Think I have a Melling 63 HV pump but out of town right now, so can't check the pump height.

Isky nodular iron rockers, no oil restrictor, 430# open spring pressure (mushroom cam) so I want plenty of oil upstairs and on the lobes.

Oil is 15W-50 Mobil 1 because it has the right amount of ZDDP without resorting to additives.
Should I run a lighter oil, change the relief spring, or just not worry about it?