Firewall replacement - what is the order for removal

[aircobra]

Looking to do the same as this  guy

 

what do i need to remove and in what order

i can see he has taken the outer reinforcement off at some point 

 

[Michael]

On my S30, the firewall was set back.  Steps:

 

1. Weld the whole car to a chassis jig.  By this one means 1"x1" uprights to the rocker panels etc, welded to the jig frame (big I-beams).

2. Cut off the front clip, just ahead of the firewall.

3. Cut out the firewall and the floor (area behind seats) in one piece; cut the floor at the rocker panels (which, as we recall, are welded to the chassis jig).

4. Build the roll cage on another jig.

5. Weld the roll cage into the rocker panels and the C-pillars.

6. Cut the floor-pan at the rear seats.  Then weld it, and the firewall, back in.

7. Weld-in the rest of the roll cage.

8. Weld-in the front clip.

9. Weld-in diagonals etc. from the roll cage through the firewall to the front strut towers etc.

[aircobra]

super helpful, thank you

luckily I only need replace about a 3rd of it, under the battery area ( its a RHD var), where the battery acid had got to you and it had a shunt at some point in time

you can see it here 

https://photos.app.goo.gl/RXs2n6Hb6L7dRYRM7

and this view

https://photos.app.goo.gl/LFhiBtxB9jTCcckn8

#1 step i get, 

#2. i was going to do the following

a. take off the top reinforcement completely to expose the welds

b. take off the rail and the wheel house

c. then chop out a section of the f.wall and replace it with this 

FIREWALL REPAIR SECTION FULL HEIGHT RHD (BEHIND BATTERY TRAY) DATSUN240Z – KF Vintage

d. then weldon the wheelhouse followed by the top reinforcement

have i got it right?