Is this lack oil to the forward rocker arms being observed with the engine running or with the oil pump being driven by a blade and drill motor in place of the distributor? How much oil pressure is there? Using the drill motor to drive the pump, observe how much oil is being forced through the tube through the pushrod gallery, etc. That tube should provide all the oil that the rocker arms need. I have never had a problem with the tube in the pushrod side.
What year is the 235 block and head? There was a change in the oil supply to the rocker arms in 1958 (or thereabouts). One of the junkyard 261s (a 1959 model, I believe) in my shop (that I have not yet taken apart) also has the tube running from the manifold side to the head for the rocker arm oil.
Search this site for similar questions.
