That tube is the oil supply to the rocker arms- - - -it comes from an oil gallery drilled into the rear cam bearing area under the pushrod cover. Depending on the year of the rocker assembly, that tube might have been squeezed shut at the factory. Some of the earlier ones were open ended, and dumped excess oil back into the valve valley.
Pushrods don't bend for no reason. Either the valve guide was fitted too tight, gum from stale gasoline in the fuel tank caused a valve to seize in the guide, or somebody adjusted an intake valve too tight and caused it to hit the top of a piston.
Jerry
