The stock tray and pan should not be used with an engine that is expected to run to 7200. If the lifters were ticking you can be sure the lower end is suffering and you need to address the delivery issue. The weak point is the suction side of the pump. If you have not upgraded the pump and pickup, and the pan and windage control, you should. As RAMM said - Milodon is best.
The #4 main starving can be addressed with the valley crossover mod. The use of 45° fittings and the angles of the holes drilled are critical to slow down the oil in the galley and let it make the turn to the #4 main. Lastly - the oil clearances and crank grinding work MUST be perfect.