I have drilled out a few to .080 each side to pressurize lifters--(that was on some solid lifter blocks((police interceptors)) other high performance blocks generally weren't drilled to oil lifters---I also did a 427 block for one of our tow trucks where I fabbed two tubes in the lifter galley area and put 16 #3 an hard lines to the lifter bosses--worked good

And you can---use edm'd hole lifters for a windsor type , feed the top nd thru hollow pushrods, and the edm holes lube the cam lobes pretty good