I would either leave it the way it is or remove the external line and see how much oil you get at the rockers.
A 1960 block with centered groove rockers and a pinched off rocker connector should give you to much oil to the top.
Being that someone added the external line makes me think that something is plugged in the original oil path, or the wrong lifters were used.
To much oil to the top end has not been seen to cause much of a problem, mainly hard to keep the valve cover from leaking.
