I fully understand the drawing. But zero oil flows to the heads unless and until the holes in the cam line up with the holes in the block. Then you get oil to the heads.
Even though a full groove bearing allows oil to the rods all the time (because the hole in the crank going to the rods is always in the groove) it doesn’t change the flow going to the heads. Unless you groove the 2 and 4 cam bearings or bring in external oil.
