After having near apoplexy after finding out the cost of the hose you
described (available only from the dealer), I devised a substitute.  Go to
the local hardware store, to the plumbing department.  Get a one inch hose
barb with standard one inch pipe threads on the other end.  Buy a reducing
coupling to reduce the pipe size from one inch to one-half inch. Buy a
five-eighths inch hose barb with one half inch pipe threads on the other end.
 Coat the threads with silicone sealer and screw the pieces tightly together.
For less than five dollars you can make this adapter.  Use one inch heater
hose to connect the adapter to the cylinder head fitting.  Attach the other
end using standard five-eighths heater hose.  Use this opportunity to replace
the heater hose which travels to the front of the vehicle.  Also replace the
metal "T" fittings which supply the rear heater core with plastic ones which
will not corrode.

  You will have to reroute the hose around the tinwork just forward of the
engine instead of passing it through the space provided but there is ample
room to accommodate this.

Rico Dagastino
Munford, TN