1972 Duster. Are firewalls different for heater/defroster models versus A/C ?

[Mike69cuda]

On a non ac car the blower hole is the diameter of the motor body.

On an ac car the blower hole is the size of the plate that surrounds the motor.

 

[Kern Dog]

They say A picture is worth a thousand words.
Equally true is you had to be there.
I see it now.

It has been awhile since I laid close attention to these. I’ve pulled them when parting out cars but never actually rebuilt one and reinstalled it. It is clear to me that the three studs/bolts here…

…. Penetrate the firewall and secure the whole unit to the firewall. I’m guessing that there is at least one flat strap inside that provides support as well as the connection to the cowl vent.
I tested the blower motor in the car now. It works and does not sound bad. I think I will leave the unit in place and let a future owner decide what to do with it.
Thanks to those that responded.
Cheers!

 

[HemiSSDart]

I’m not understanding that. The blower motors of both units look to be integrated into the whole structure of the box.

Yes, but the non A/C box has four bolts that attach it to the firewall while the A/C box blower motor just goes through the firewall...

 

[matthon]

Are the only differences the 2 a/c line holes to the right of the heater hoses, and the a/c fan has a larger hole?

Is the non a/c fan hole and the a/c fan hole concentric circles, aka same center point?

 

[str12-340]

Heater cores for AC and non-AC are the same for the '67-'72 A Bodies.

sorry, this is just not true

s the non a/c fan hole and the a/c fan hole concentric circles, aka same center point?

sorry, but they are not concentric, but there is a thread here somewhere about installing Classic Air's kit, made for the non-AC firewall, when you have a factory air firewall. The adapter that is used for this should work to put a N0n-AC box in a Factory air firewall. Here is the adapter plate behind the AC fan hole. You can see where the non-AC hole is compared to the AC hole. I believe that a search for the classic air install will yield the source. You would need a dress plate on the engine bay side to produce a finished look.

This is the finish plate that I made for my CAA install

 

[Kern Dog]

YOU had to make the finish plate? The kit only came with that plate mounted to the inside?
No offense but if that is true, that sucks that YOU had to do that. The first picture looks like a shade tree mechanic patched together stuff to make it work, not something from a company selling a kit.

 

[340sFastback]

sorry, this is just not true

Same Heater core? | For A Bodies Only Mopar Forum Same Heater core?

 

[matthon]

Agreed, Classic Air's plate looks like garbage, just a smaller single hole, why do they even bother.

Can I swap any a-body a/c setup into my big block 67?

I understand I'd have to make the fan motor hole larger, and add a few holes for the lines.

The pics I took are from a 67 383 with what appears to be a factory air setup.

 

[str12-340]

appears to be a factory air setup.

Factory had a very large 2 cylinder compressor. What is on the set up in your picture is a modern Sanden Compressor, which is a legitimate upgrade

Factory air and compressor:

 

[matthon]

Yup, but the rest looks legit.
Not sure about that idler pulley, but probably stock to some Mopar.