If the oil holes weren't drilled in the lifter bushings before being installed I don't think you'll be able to drill them. Run the solid flat tappet, sell what you have. Sorry though the cam is kind of small for me. I'm still thinking about the lifters but you might be able to make a better deal with someone as a package. If you don't sell them let me know. I don't need them right now so it's not a big deal but having spares is always a good idea.