If he is restricting the oil at the cam bearings by drilling a hole and turning the bearing if he does that on number two and number for his blocking oil supply to the cylinder heads. Therefore he would need to crossover tube to feed oil to the driver side head port 4-channel whatever you want to call it or drill through the channel into the main galley and then plug the outside hole to get oil up to the cylinder head. That is if he is blocking the oil passage down at the cam.