Heater/defroster help

[416Ford]

I have the heater out of the streetrod trying to get better defrosters. Not sure what the heater is originally out of but I think it is from one of the 41 Fords that I used for parts.
Fan is reverse polarity and blows excellent in both directions. All the air for the defrosters is exiting between the defroster setup and box.
Should the space be blocked off originally? My fear is that I will burn up the fan when it is on heat if I close it in.
The box mounts up against the firewall so there is minimal openings in the back.

https://photos.app.goo.gl/fpzbFh6surg32sAL7

[enjenjo]

Have you considered putting computer fans in the defroster ducts on a seperate switch? I'm not getting a clear picture in my head how this works.

[416Ford]

I though about it but didn't want them in there unless it was the only option.
I must have worked correctly back in the day......
I will toss it in the car Saturday also.

[Canuck]

Looks like air should come into heater from behind front shroud, thru 6 blade fan  then heater core (missing) then out thru 3 front doors.  

Defrost should have a centrifugal impeller in rear of motor sucking air from behind front shroud and exiting thru ducts at top.  Should be some adjustable dampers to restrict flow as desired.

[416Ford]

Core is out to show it better.
The defrosters do have a flap in them., and there is not place to mount a fan behind it, that is why It has a reverse polarity motor.
I open the door on the box for incoming and exiting air.

[ragdol]

It appears to me that the air, with fan in reverse , should open the flaps, that are wired shut, in the defrost tubes because the pivot is off center. The flaps must pivot freely to operate. Do you have them wired open? That probably would work as good as it can.

[416Ford]

Yes, the defroster tubes are wired open.
I picked up a piece of 6" heat duct to tray and wrap the space with. It's an 8" diameter so I will still have some fresh air intake.
Now I am to busy to get back to it until we get a rain day.

[416Ford]

Frank, did you see any pictures of this fan set-up?


Similar to mine and it is not block off either.