273 rocker arms

Just remember the shafts are hardened & it may take a bit to drill the holes without breaking bits.
your right, My cut off wheel made quick work of the banana groove but the holes are proving tough to drill. Ill have to spot and hit 'em with the drill press with a good bit. Only drilling the adjuster oiler for now, will see how the bit holds up. If it cuts, Ill cut the stem oilers in the shaft and arm.