Engine oil leaks from the valve cover gaskets, timing cover gasket, intake manifold gasket, distributor o-ring, and rear main seal area are common. The leak at the rear main seal area is generally not the seal itself but the bearing cap to the engine block seal. An oil leak could also be internal to the distributor, if oil is found inside the distributor then the distributor should be replaced.
Car Problem Reports
Dodge W150 Engine Oil Leaks
Dodge W150 Problem
Engine Affected: 5.9L V8
Visitor, 1990 Dodge W150, 5.9L V8, 162,534 mi
So far I have had an oil pan leak were waiting to get it put back together to see if it countinues