E-body Firewall, need some advice

[ambitions2]

I am at the stage now getting ready for sandblasting.  So I have a few questions, but my main one right now is dealing with the firewall.  Below is a picture of my firewall, and you see where I circled that section in red, that is rusting through.  I remember reading earlier I think that the B body firewall is a modified E body firewall?  Can I use a B body firewall piece to fix that?  Any suggestions or comments would help.  Thanks guys. 

[360 'CUDA]

Here is a pic from my 74 Charger. As you can see it is similar on the right side but quite a bit different towards the left

[miketyler]

if thats all you have, you ought to be able to patch that in a snap! I had to replace my firewall and cowl section as I had holes like that inside the cowl.

[Stacked440]

Anyone else notice the big gob of fiberglass in the bottom of the first picture?  Least thats what i make it out to be.  Gonna wanna patch that bugger to

[ambitions2]

Anyone else notice the big gob of fiberglass in the bottom of the first picture?  Least thats what i make it out to be.  Gonna wanna patch that bugger to

After it comes from sandblasting I should see the TRUE condition of the car

[dougs bs23]

Have you taken out your heater box yet?  you may want to "poke" around the upperinside around the areas where the cowl and wall come together, as there was very little paint or sealer originally and this spot seems to collect water and debris.    Hopefully you wont have it looking like swiss cheese. If thats the case, you may want to remove the cowl b4 you blast it as you may also need to clean it up and fab some new metal to patch it. Also  check around  your freshair intakes (non A/C) as this is another area that rot can be hidden.  Good luck and happy blasting