[RedDirtRoad]

The heater box photo you posted looks like the A pillar isn't rusted
Looks like its just the flange that is rotted out.
You need to remove the heater box which is no small feat if you aren't doing a frame off restoration.
If you do remove the box and the evaporator in the engine section you will see that flange is 2 piece and screwed to the A pillar with 5/16 self tapping screws,
I just bought the 2 piece flange myself, Hard to find , not cheap

[ZeGermanHam]

Originally Posted by RedDirtRoad

The heater box photo you posted looks like the A pillar isn't rusted
Looks like its just the flange that is rotted out.
You need to remove the heater box which is no small feat if you aren't doing a frame off restoration.
If you do remove the box and the evaporator in the engine section you will see that flange is 2 piece and screwed to the A pillar with 5/16 self tapping screws,
I just bought the 2 piece flange myself, Hard to find , not cheap

I am doing a frame-off resto, but haven't gotten to that point yet. In the meantime, I guess I'll keep an eye out for a heater box and flange that's in better shape than the tattered remains that I currently have.