Heater Fan Cage

["Tom Witt" <wittsend@jps.net>]

 Is there a "findable" donor car for the heater squirrel cage? They seem
rather generic. Mine (like everything else on the car) was broken where the
retaining ring goes and it wobbles excessively.
 Also there is an circular opening between the fan motor and the housing of
about an inch. Is this the way it is designed, or is there some type of seal
missing? It seems that the gap would limit the ability to draw air through the
heater core exclusively.
Thanks, Tom Witt