Water Reservoir

[osprey877]

Attached is a photo of the fresh water cooling system on my four cylinder Pathfnder diesel. I am rebuilding the engine with a new longblock. My problem is that the new head is missing the water outlet on the block for the hose #1 on my diagram. On the old block, there is a 1/2" tapped hole in the block that takes an NPT nipple that connects hose #1 to the top of the water reservoir as shown in the diagram. I assume it is for purging any air that gets into the system.
There is no hole at all in the new block so I need to either replumb hose #1 to some other location on the engine, or dispense with it entirely. Hose #7 is of similar size and plumbs into the top of the heat exchanger so I'm thinking maybe it performs the same function and I could tee off of it to the water reservoir.
Any cooling system experts out there that can help me out??

[osprey877]

I also wonder why it is that the reservoir tank on my boat has three lines going into it, whereas the tank on my car has only one. Is this standard operating procedure on all marine diesel engines, or is mine an unusual configuration?? How many lines/hoses does your tank have?😁