08 The holes in the rocker shafts have to be properly aligned with the oil delivery hole in the head so that the rockers can be fed the lubrication they need. Stock rocker shafts make this easy with a notch that should always go to the left and point down when the shaft is installed. But an aftermarket shaft may or may not have the notch (this one doesn’t). The easy way to get this right is to always install the shaft with the small oiling holes pointed down and angled toward the exhaust ports. Page also recommends removing one or both of the end caps, so that you can properly clean and inspect the inside of the shaft. You don’t want any dirt going into the rockers and ruining your valvetrain as soon as you crank the engine. Replacement plugs should be available from the manufacturer.