Need Advise on Firewall Cracking

[cuda2002]

I am looking for some advise on a problem that I have discovered on my 73 cuda.  I have found that I have a crack in the firewall just behind where the hood spring mounts to the inner fender.  I have attached a couple of pictures to show what I am talking about.

As you can see, it looks like someone tried to fix these cracks by welding over them sometime in the past.  I guess that gives me some comfort that this isn't a new problem, however, I am concerned about it and think I should probably find a way to do a proper fix on this. A couple of questions: 1.  has anyone had this problem before, 2. What causes are attributed to this type of cracking, 3. How do people typically repair this cracking and 4. has this be successful in preventing re-cracking, 5. am I over reacting to this?

As the car sits now, it has a 383, I have welded in some sub frame connectors and an XV motorsport rad support member.  When one of the previous owners dropped in the big block he had also cut out this rad support. I am assuming this is probably the answer to question 2 above. I don't know exactly when the big block went in but Since I bought the car I don't think I have put more than 100 miles on it

Any help would be appreciated.

Thanks in advance. 

[Chryco Psycho]

I would plate over it from the rear if the metal is strong enough to weld to it , I don`t think you are over reacting to this , it is an obvious stress crack & will only get worse as well as allowing moisture into the car which is not going to help the floor pans

[426HEMI]

I would also recommend to drill a hole in the crack leg that is coming off of the main crack at the end of the line. 

[A R T]

Cut it right out of there. I would trim around there, then fabricate a new piece of firewall, as well as a new section of inner fender well.
Dont just try to weld the crack, it will not last.

[cuda2002]

Thanks for the feedback guys. I was planning on pulling the engine in the fall  to detail the engine compartment and do the front end work.  I agree that cutting out the crack and putting in a new piece, as was suggested, is the way to go. Some re-inforcement is also appropriate.

I had been hoping to put a few miles on the car this year . Is this serious enough to kill that thought? Clearly no racing or aggressive driving!

Also, if you could comment on how these cracks might have developed so I can address that too.

Thanks again.

[Bullitt-]

Looking at the first pic, just forward of the hood hinge something seems amiss.  The hing seems to be buried in the inner fender, so I'm guessing there was some damage there that has been "repaired".   My car had a front end collision & the inner fender bent right in front of the hinge.

[73Chally]

I hate to say it but I bet you'll find a pretty ugly mess under there once you get the hinge and paint off.  our best bet will probably be to cut it out and repair with new metal.

[A R T]

Sure, go right ahead and drive it. No worries about more damage unless your planning to beat the snot outta the car.
What caused it is a bit difficult to determine until you uncover it in there. Remove the paint and the body filler we suspect your gonna find in there. At that point you might find some collision damage, or perhaps someone did a poor job replacing the inner fender? Hard to tell. In a hard launch, that corner typically lifts up, which loads the forces on the inner fender BACK into the firewall area. The firewall on E-body cars has a history of rust damage, due to a few areas that moisture can get into it.
Good luck and be sure to let us know what you find when you dig into it.

 

[mopar12372]

 enjoy the car , when your ready then take care of it . welding , cutting it out and replaceing metal will fix the crack . i wouldnt worry about it.