In my 8 the oil pressure was low when hot. When I rebuilt the engine I closely examined the oil pump and found no obvious fault, the bearings had excessive clearance and I believed this to be the problem until I examined the oil flow through the block.
In the 8 engine, full oil supply from the pump is delivered to the middle camshaft bearing and then passages direct oil to the bearings etc.. When I measured oil clearance of the middle camshaft bearing it was found to be almost “.020”, approximately 10 times standard. Obviously a large proportion of the oil delivered from the pump was being lost from the middle camshaft bearing straight back to the sump.
As the cams runs straight in block its not a simple matter of replacing the cam bearings. By chance I had a spare camshaft that had over size journals and had the block bored to suit.
When assembled and run the oil pressure was to specification.