Ok the two hoses your fingers are pointing at are vents for the float bowls. They run up to barbs in the carb body. They put the hoses on to help outside crud from getting in the carbs.
The two barbs on the float bowls are the float bowl over flows. In the stock form hoses were on them that ran down behind the engine. This kept the over flow from staining the top of the engine. You can add hoses to them.
www.amckayltd.com/carbguide.pdf may help you with your carbs. We have found it indispensable. Some call it the carb bible.
On the leak from the head gasket A retorque of the head bolts often fixes the leak.
Follow the order in the repair manual. Remove each nut or bolt one at a time. Clean the threads. A coat of motor oil on them. Reinstall and torque to spec.
Except for the 8 large chrome nuts. These need some special attention. On the 4 outside nuts they used a rubber composite washer. These four studs are oil drains from the head. The rubber washers were used to seal the oil drains. But over time the rubber goes bad. This lets a bit of oil leak and they won't hold the torque. Most replace them with the proper copper or brass washers. The 4 inside studs are not drains and use steel washers. So they are fine.
One more thing The stock spec for the torque on these 8 chrome nuts is 25 ft./lbs. Increasing this to 30 ft./lbs. will help reseal the head gasket.
once redone clean the area very and watch for leaks.
Works better than 75% of the time. Maybe closer to 85%.
Leo