I have a problem with a SBC 400.
The eninge Spec:
Eagle steel crank, 6" rods, Melling HV pump with strongest oil relief spring, roller cam, roller rockers, no oil restrictors (Crane adviced against), Milodon 31145 sump. Valvoline racing oil.

Oil pressure was low at idle, so I striped the motor, and found all bottom end bearings damaged from oil starvation.
So I replaced the bearings, polished the crank, and got 2-2.5 thou clearance through out. I checked the pump over, and ensured that the relief piston was sliding freely.

Started the motor, and got 35lbs hot at low RPM idle. Rev the motor, and the pressure climbs to about 70lbs at about 6500, raising the RPM causes the pressure to drop to about 45lbs at 6500.

I'm baffled.....
Limey