No need to drill the outer race. Like Jerry said, just let the oil leak out the ends of the bearings.
I’m not sure that would work. The outer race with a slight press into the rocker would seal off any chance of oil reaching the weep hole in the top of the rocker. It’s my understanding that the weep holes are what supply oil to lubricate the both the top of the valve stems and the push rods. In addition, the pressure loss from the open ends of the bearing may be to much to allow oil to reach the weep hole, even with holes drilled in the outer bearing race. It’s possible the oil weeping out between the rockers and spacers, might carry enough oil to lubricate, but I have my reservations.
Just thinking of some possible issues.
