The Triumph rocker shaft assembly not only suffers from being poorly designed, but the design issues which lead to short component life are accelerated by the lack of adequate lubrication being delivered to the rocker shaft assembly.  The installation of a supplemental oil line increases the volume of oil delivered at the rocker shart, increasing the life of the rocker shaft components.  Your oil pump and oil relief valve assembly should be in optimum condition when installing this extra feed line. 
This is a must fit upgrade if you are running roller rockers.
Performance engines built by Wishbone Classics do not require this feed line, we can make multiple modifications to the internal oil delivery system in the engine block to increase oil volume to the rocker shaft assembly.