A fan in a 401 air duct!
 

Has anyone assisted the airflow through the 401 air ducts with a fan? OK when the car is moving (sort of) but not when stationery.

Recirculating heater
 

Faced with the same issue in my 401 (no heat when stationery) I fitted a new internal heater blower unit which fits nicely and unobtrusively between the gearstick (long type) and the firewall. It just needed rerouting of the flexible heater hoses to feed it and the fan motor is variable speed.
This one is australia stock but like most items its can also come from china for $20 or so less:

https://www.ebay.com.au/itm/Car-Truc...8AAOSwpdJdPrW-