Firewall Repair or Replace

[nicka]

I'm looking at a lot of rust and holes all along the firewall that resides underneath the cowl area.  The lower area of the firewall looks ok. I think patching the rust holes is out of the question due to the rust and holes all along the length of the firewall.  So looks like I'll have to order a new AMD firewall. 
Has anyone removed just the old upper firewall area and replaced it with a new sectioned piece? Cut the old metal just above the lower cowl and lap weld it from the inside ? The floor is out of the car.

[Rich G.]

At this point I'd replace the whole thing. You already got the floor out by the time you cut it off the lower cowl who knows what will be left to even weld to. I replaced the whole cowl on my cuda and it wasn't that bad considering it was a lot of work.

[Dmod1974]

I replaced my firewall and cowl with AMD.  If you go that route, absolutely mock up the pedals, column, and dash before you paint or go back together.  My firewall bracket was way off and I had to remove and reweld it.  Luckily, I'm still in the metal work phase but it would have been really bad if I hadn't taken the time to mock up everything.

Also check your wiper cowl trim fit.  I had to slot the holes slightly on mine.  Basically, test fit EVERYTHING and don't be surprised if you find things off.  I also sealed the cowl vent areas heavily with seam sealer since I don't see how they could be water tight without it.

[jimynick]

I replaced my firewall and cowl with AMD.  If you go that route, absolutely mock up the pedals, column, and dash before you paint or go back together.  My firewall bracket was way off and I had to remove and reweld it.  Luckily, I'm still in the metal work phase but it would have been really bad if I hadn't taken the time to mock up everything.

Also check your wiper cowl trim fit.  I had to slot the holes slightly on mine.  Basically, test fit EVERYTHING and don't be surprised if you find things off.  I also sealed the cowl vent areas heavily with seam sealer since I don't see how they could be water tight without it.

While I, too, replaced the whole cowl/firewall/frt floor panels I had no misery regarding bracketry nor holes. What we did, was we bonded the cowl to the firewall before installing the assbly in and tying it into the new floor panel. There we did have to screw around a bit and had a 4X4 on a floor jack into the trans tunnel to help align the firewall/floor flanges. Buy yourself a few more vice-grips or Clecos when you do it. You'll thank me later. take your time, measure and re-measure and then measure again and weld once. You've got this. 
PS- the bonding kits make a helluva sealant too!

[RUNCHARGER]

The bonding works awesome on 4 speed humps as well.

[nicka]

I called AMD and the firewall with a/c have been discontinued for over a year.  Ouch.  Time to check other vendors.

[nicka]

When I purchased the car,  the previous owner stripped out the a/c components except the blower box which means I have to start all over.  Since this car is not a numbers matching car, maybe I should purchase the non a/c firewall and purchase the latest a/c units?  I heard the latest a/c units are a lot better like Classic Air.  Worst case scenario would be to get the non a/c firewall and cut out and replace the a/c portion of the firewall.

[nicka]

I just got off the phone with Classic Air and to use their complete system, they only need the heater hose so the non a/c firewall will work.  All good points to purchase the non a/c firewall.

[RacerX]

When I purchased the car,  the previous owner stripped out the a/c components except the blower box which means I have to start all over.  Since this car is not a numbers matching car, maybe I should purchase the non a/c firewall and purchase the latest a/c units?  I heard the latest a/c units are a lot better like Classic Air.  Worst case scenario would be to get the non a/c firewall and cut out and replace the a/c portion of the firewall.

I am in the same situation with my 71 cuda...  the cowl and firewall have a lot of rust and
at first I was considering it an opportunity to add factory air by using the A/C firewall.  But
after looking closely at the Vintage Air system I decided to just use the non-A/C firewall and
run their system.    It is not necessary to have an A/C firewall for their system, and inside the
car it looks factory stock, except for the little blue light at the switch panel.   

The only factory A/C parts you need with their system is the dash vents.   They have their
own aftermarket vents if you have a non-A/C car but I like that it can tie into the factory
vents and appear stock.

[nicka]

My 71 barracuda originally came with an a/c so I have the original vents.  I spoke with Classic Air and their kits allow to hook up with the original vents or their own.  I heard the newer ac units are more efficient. Also, I picked up a Shaker hood while at Carlisle and the Classic Air uses the Sanden compressor.

[RacerX]

My 71 barracuda originally came with an a/c so I have the original vents.  I spoke with Classic Air and their kits allow to hook up with the original vents or their own.  I heard the newer ac units are more efficient. Also, I picked up a Shaker hood while at Carlisle and the Classic Air uses the Sanden compressor.

I like the Vintage Air setup for the more "refined" look of the interior parts, but either vendor will do the job with nice, new, modern components.

[nicka]

I guess another option would be restore the a/c heater box and cut out that area of the firewall and weld it onto a new firewall and order remaining new a/c parts.

[Rich G.]

Boy it seems like AMD is getting out of the E Body business!  That's disappointing for the hobby considering the only project cars left are rust buckets!

[RUNCHARGER]

AMD is going all out in GM and Ford stuff now.

[nicka]

The firewall is out.  I like the idea of panel bond.  Wonder if they make a panel bond that matches the color of the original sealer?  Mocking up is a good idea.  I'm thinking about painting underneath the cowl area before panel bond.  Thinking about keeping the original a/c heater box.  I found two vendors that sell rebuild kits.  Looks like Classic Auto Air will hook up to an original a/c heater box.