on my 273 iron rockers with the threaded adjuster removed I drilled a 1/8" hole horizontally thru the rocker on that side from the outside in & on thru the shaft all in a straight line clocked with the valve closed then drilled/tapped the outer hole in the rocker for a setscrew which stops high RPM oil castoff from it which is a waste & also helps lock the setscrew in place as some of em ain't tight enough (not enough interference fit on their threads)