1985 90hp Water Pressure Gauge Hookup?

My boat has the water pressure gauge in the dash so I thought I would hook it up. The engine is a Yamaha 1985 90hp 90ETLK, Can someone tell me where I hook up the pressure gauge?

Thanks again,
Jerry...

[boats.net]

Water pressure port is by cylinder head.
40-90TempSenderPort.JPG

I finally got the chance to work on the boat again...I have a water temp gauge sender in the spot you pointed out to install the water press gauge. Is there another place to pick up water pressure or is there an adapter to install both senders in one hole?

Thanks again for the advice,
Jerry...