The edge of the firewall on the cab needed patching. As I did decide to go with “quick & dirty” repairs to the cab, I decided to cut this flange off and just weld a piece of metal across the gap.
So the rusted mess was cut free, the paint & surface rust were ground back, and a piece of steel was bent into an L and welded across the gap.
This is where I ended up. In addition to being easier, this removes the lip that was trapping mud & water and encouraging rust. The lip is still in place above where the fender sits, so it’ll look normal under the hood once it is re-assembled.
It turned out to be a right pain in the ass to weld the lower parts of this. The weld kept trying to drip off the metal rather than stick in place, and I couldn’t find a good technique to avoid that. So a lot of swearing later I slowly manage to tack it all together.
Once the welding was done and ground down, it was painted with the same tractor paint as the rest of the firewall.
Then the whole firewall got a coat of truck bedliner, which, in addition to being very tough, did a great job of hiding the runs & other issues from painting the firewall.
But first I needed to patch the other section that you can see cut out above. There is 3 bends here that needs to be carefully made so everything lines up. I got a brain wave and measured the lip at the top of a junk fender I had. Everything appeared to match so I cut out a section. 
I flipped the piece over and tested it, the bends are an exact match. I carefully trimmed it and the fender edge to fit and tacked it into place. 
Here it is tacked in place, please ignore the terrible welds from forgetting to turn on the shielding gas on the MIG. Below is the piece with the welding finished & ground down. 
I decided I was tired of welding, so I worked on something else for a change. I decided to paint the now exposed parts of the frame & firewall. Normally the firewall should be matched to the body color on these trucks, but since I am not sure what shade of dark green I ‘ll be using I decided to paint the firewall to match the rest of the sheetmetal in the engine compartment so I didn’t have to worry about it matching the outside.
And here is the frame & firewall freshly painted gloss black. I used tractor paint as it is supposed to have good durability. The frame came out great. However despite looking good in pictures, the firewall has a lot of runs & brush marks. I let it dry for a few days anyway, and decided to cover it in textured truck bedliner to hide the flaws.
Once I had the front of both inner fenders patched, it was time to strip the rest of the front off. First the radiator support came out, which was just as much of a 
