The supply from the oil pump divides and goes to two places. One feed goes to the block to supply the main bearings etc. The other feed goes to the oil distributor valve, which is external and under a little cover on the driver's side of the block. The valve opens as pressure builds up to normal during startup. When it opens, it feeds oil to th rockers, and to the connecting rod sprayers. You could disconnect the distributor side of the little loop line , start the motor and see if oil runs out. This line only feeds the rockers.
