In case it was overlooked, The hole in the old manifold leads to a big open area that is the lifter galley. Like pouring oil in your roof vent of your house , the attic is the liftergalley. The oil needs to be in the basement and would get there eventually, just like your sbc. The heads drain their oil into this area. All the 60-70s sbc use the same v/c except the early 265 ppacks.