No repairs of any kind have ever been done on this chassis. The outer rockers look like they had never been romoved.
The rust in the engine compartment looks fairly typical - battery tray and engine shelf perforated.

Once the engine shelf and battery tray were removed the amount of damage became more apparent. Both the engine mount and suspension console need repair in addition to the top of the frame rail and the upper wheelhouse behind the battery tray.

One other panel that is usually involved in hell hole rot is the corner of the firewall on top of the frame rail. Here's a pic with the perf already cut away.

The wheelhouse patches are in and the welds have been lightly dressed.
These pieces were hand made, and only as large as necessary to remove pits and perforation instead of replacing the entire section with the Restoration Design piece.

The suspension console was opened up and checked for weakness in the lower section. Although there ws significant rust inside, the strength seems good and there were no deep pits. I opted to clean the rust as well as possible through the hole and brush POR15 over all the accessible surfaces before installing the patch.
The little drain hole at the bottom of the ear was cleared of debris as well.

Here the patch is tacked onto the console.
I also POR15'ed the bottom inside of the frame rail to the extent that it was exposed to me. It looked real good in there and only needed light surface rust removal before painting. Once the top of the frame rail is patched I need to remove the rest of the engine mount because the rot goes right to the bottom.

I don't usually see this section being so bad unless the car has a lot of rot.

A tough spot I have to deal with is the driver's side hell hole. A small area of the engine shelf near the plugged drain has some perf. It's a difficult shape in a tight area and I don't really want to cut it wide open if I don't have to. Too bad RD doesn't make a repair panel for the driver's side engine shelf.
This pic is from below, with the perf circled.

So far the only other areas I have found in need of patching are the door sills at the back where they meet the rear door jamb. These are small patches compared to what I often have to do.

and

I was told this car sat in a dry warehouse in Nevada for years.

Looks like your'e having tons of fun there. I am currently working on the exact same stuff right now. With the exception of my rear floor pans are toast also. Gotta love battery acid. Keep up the progress.

If I didn't know better I'd swear that was my car.... exact same damage. WOW.

Nice work Chris. Threads like this are classic.

I am not suprised at all at the quality of Chris's work. It was awsome checking out his shop. What a perfect business to have in the rust belt

Chris do you have a picture of the firewall patch + the top of the long (below where battery tray was)? These sort of pictures give people like me the confidence to hack out the rotten metal and weld in a new patch. If i see your pics i have something to aim to.