I'm assuming you're oiling up through the head and not through the pushrods.
If you're not getting any oil up to the head feed, you'll have to backtrack and see where the restriction is. The BBM blocks have a threaded hole where the feed comes out of the deck surface. If it's not plugged, then it's quite possible that a cam bearing was installed incorrectly. The BBM blocks use a Side Oiler style bearing, where the feed hole has to line up with the hole in the main saddle and also line up with the hole that leads from the cam tunnel to the block deck.
Also possible that the #4 cam journal isn't grooved, but that would be a very, very rare occurance.