As I remember the
oil flows through a series of intertsecting drilled holes that are pluged where they come to the surface. For the most part all FE engines are the same except for the 427 side oiler. The higher performance versions and themodified oness have screw in pipe plugs rsther than the pound isn soft plugs. The plug in the center forward facing
oil gallery under the timing chain cover should have a orifice (small hole with a cotter pin that will move around, ever so little, to keep the hole from plugging shut) this hole. This hole vents any air in the
oil gallery almost immediatly but flow will lessen when the oil arrives an dslow to a small streme spraying oil on the timing chain. Watch the cam thrust plate bolt holes. One of the threaded thrust plate bolt holes is also part of the oil gallery. Take care that thethreaded hole has a clear pathway for the oil flow to distributer shaft. We used to tap the threads in the older FE blocks ( those cams were were originally retained in ward by a spring and an alluminum bumper against the inside of the timing cover) and then take a rotarry file to the threads inside the hole make a clear oil path on one side of the bolt for oil th flow. Take care to not use too long a bolt , this where the oil that lubercates the distributer shaft tip just above the oil pump drive in the block. I had a friend that missed this and had the block and distributer shaft seize together. I used th clean up the (enlarge) the galleries (holes in the block) from the oil pump to oil filter hanger, in the alluminum oil filter hanger, and out to the block taking care to keep any holes inside the gasket channels, no use in undermining the gasket. Nice big smooth holes that do not inhibbit oil flow. You want flow mostly with moderate pressure. Too much oil volume and pressure ( pressure is established by bypass piston and spring inside the oil pump) will challenge the distributer drive ( usually the pin in the gear and the oil pump drive. Do not get carried away with shimming the relief spring to create too much oil pressure . The oil pump drive is only a 1/4" hex in cars but is 5/16" hex in trucks. The oil pump internal hex and that end of the shaft wear most. I used a blue printed high volume Melling truck oil pump and the heavey duty stepped oil pump drive shaft.