Firewall repair

[Shoooter]

A good friend of mine is looking at a 70 challenger. It looks like there seem on the firewall is swollen and will need some work. He might be able to patch it. My question is if he has to replace the firewall do the engine aprons need to come out to do this or is there enough room to remove the spot welds from the aprons to the firewall and leave them in? 

[A.Gramz]

I did mine with the inner fenders in place.  also help to realign the firewall in the correct locations