don't just become a parts replacer.. learn how to diagnose, and determine the cause of your problem..
If you are like me and drive your Model A when it is less than warm out, and have a manifold heater but are still cold, the fresh air hose that fits the fan shroud on a '62-up Volkswagen will fit nearly perfectly into the firewall duct on the Model A, allowing you to aim the heat directly at you or your passenger. When it is single digits, the heater in my '31 made me decide I really ought to install hot water heat, but it is a cheap, quick and easily removable improvement in the meantime.