Break In Disaster????????

With 10W30, 85 psi seems too high for a standard Melling pump. So did you rev past 2300 and see what the pressure did, or are you saying that the pressure leveled off at 85 psi for RPM's higher than 2300?

Time to check with another gauge IMO, and check at yet higher RPM's to see if the pressure keeps on climbing. The 85 psi is a potential concern (to me) for something not right around the relief spring in the oil pump. Yes I would suspect the oil pressure is a possible issue for the rocker; the other prime suspect is a fully grooved cam bearing, or something around the rocker shaft hole.

BTW, did you check the hole diameters in the rockers? They should be .375". (3/8") As I understand it, the rockers are the same with and without banana grooves.