Mid 70's 360 motor mysterious water leak

No one mentioned it may be the timing chain gasket, or water pump gasket. Could be either one of these if the above don't work.
^^^ agreed & also a too thick of the cork supplied gaskets on each end (from head/deck/intake milling) can hold the intake up just an inperceptable amt when it is bolted on, enough to cause one or both of the front head to intake gasket water port interfaces to leak slightly. If needing to go thinner I use silicone instead. EDIT & they (the cork ones) might not leak right away.