To answer your question, you can only "put a wire down there" the thickness of the head until it hits the deck of the block. There the oil passage makes a jog then down thru the block to the center cam bearing. Actual flow starts from cam bearing up to rocker arms.

BOB

Have you checked the shaft(s) to be sure they are not plugged up as many did over the years?They can be cleaned out by diassembling and taking the plugs off the ends.There are also squirt holes in the arms that get plugged and can be cleaned using a paper clip with the rocker shafts dis-aassembled.You also should check if there is oil flow from the camshaft bearing by taking shaft off and checking for oil flow from the oil feed hole in the head.

  

You guys probably already know what I am talking about, my drivers side is oiling fine, but the passengers side is non-existent.

My question is, it looks as if the oil squirts from the bottom downward. To see if the hole is plugged on the otherside, do I need to take the rocker arms off to put a wire down there?

1957 Fairlane