Frank, The oiling for the rockers on a 1955 235 begins behind the side cover at the very rear. The block is drilled through into the camshaft oil gally and has a restrictor fitting with a 1/16" orafice in it. From there a tube runs up and forward to the center of the block, up around the head bolt, through the head, up through the oil distributor/rocker connector, and out to the shafts.
One of the most common places for the oil to be stopped is the 1/16" orafice fitting. Occassionally the tube can also become plugged.
