I built a 500" RB for a customer, (stock block) and used the oil pump that was on the old engine. It's a Melling HV oil pump with a Milodon cover, single external line from a Milodon static pick up. When I primed the engine new, it had over 100 lbs of oil pressure. I replaced the oil pump regulator and spring with a new one from a Milodon overhaul kit. That brought the oil pressure down to about 85-88 lbs with a drill and priming shaft. I'd like it around 70-75 lbs idling. Whats the best way to bring this down?

Thanks,
Brian