Flyer,
What you've located is the oil transfer manifold (the plate with the three screws behind the exhaust manifold) and the oil transfer tube which delivers oil to the overhead. The transfer tube connects to a fitting adjacent/rear of the plate, makes a short "U-turn" and enters the blockto pass through the water jacket and into the pushrod cavity on the opposite side of the block. From there, the tube runs up alongside the pushrods and into the head where it connects to the rocker shaft assembly. If this jumper tube is missing, you need to install a new tube: see
this description in the manual for "oil distributor to rocker shaft pipe" and
here for the part from a vendor.
The fitting for the oil pressure gage connection is farther down the block, forward of the flywheel housing, near the water jacket drain.
I've recently made this repair. It's not too difficult.
Have fun.
Bill
