What year is your engine? This is a 235, right?
On 235s, there are two oil ports on the drivers side of the motor. Both are right above the oil pan rail and behind the driver's side motor mount on the engine block. They are 1/8 pipe thread holes. One is the main oil galley from oil pump. It will be the hole in a round "riser" running down the length of the block. This is where the supply to your filter, and oil pressure gauge should go. The other is a dumb hole in the block that dumps oil from the filter back into the pan. The 1/8" pipe thread hole on the passanger side of the head is an optional oil supply line to the head. It isnt used unless there is an oil supply problem to the head.
On 54-55 engines, the oil to the rockers was supplied by the rear cam bearing, thru a removable line, to a 1/8" NPT passage inside the pushrod cover. 55-62 engines didnt use this line. The 1/8 npt hole is plugged, and oil is supplied from front and rear cam bearing, thru lifter galley, up thru a drilled passage that leads to cyl head. If the line or the block passage gunked up or was otherwise obstructed/damaged/nonfunctional, you can supply oil to your rockers by feeding oil to the optional 1/8 NPT hole on the pass side of the head. This may be the line you're seeing going to the pass side of head. If it is gunked up or connected wrong, then the rockers will starve for oil.
clear as mud?
chip
