hi, lifter bushings are for solid or rollercams. they cut off the oil to the lifter body. the oil passage in the block will have to be drilled full length, so the lifters will get pressure. this is not a cheap repair!!! just food for thought
I see no reason why you couldn't drill the bushings for oil supply to a hyd lifter and just make sure that the hole lines up with the oil galley when it's pressed in. The oil passage in the block is already drilled full length. Not sure what you mean by that.