Oil pressure problem could be several things. Cheapest is bad pressusre sender located next ot fuel pump, to bad a pump or worn parts. I would first change the sender unit. During hot weather, I use 20W50 in mine and the pressure holds great even on extended trips.
The oil comming out the dip stick may be caused by blow by on the cylinders and pressurizing the oil sump area or the PCV system. I would check the PCV system to make sure you have the proper circulation of air and elimination of vapors. It should take air in to the left side valve cover and **** vapors out the right side valve cover via the PCV into the intake manafold. Common problems in this system are bad PCV valve, plugged hose from valve to base of carb, and clogged filter on the intake side. Since you have a 351W I would expect that the filter is in the air cleaner compartment with a hose running to the oil filler cap. (picture attached).
Good luck,
>-