Triumph Repair: Rocker shaft oil piping, rocker shaft, cam shaft

Question
The PO on my 69 1300 spitfire engine had added an extra oil line from the block to the corner of the head. I know this goes to the rocker shaft, I have heard that the internal port should be tapped and plugged if this piping is used.Should it be plugged? does this oil line help/hurt? if it's not plugged should I remove it? Thanks

Answer
Hi Terry,
I don't have any data on it, but the line should supply sufficient oil to the rockers. They are probably talking about the port between the head and the block which gets oil from the rear cam bearing and that is restricted by only supplying oil when a flat on the cam shaft lines up with the oil hole. After the engine is warn that system does not supply enough oil to the rocker shaft so that external line was added. I believe it would be a good idea to plug the block if the line system was installed. This would increase the oil pressure and quantity to the rockers if the rear cam bearing was worn.
I don't have anything in print but that is my opinion.
Howard