This car was and still is a lost cause IMO. I made it good enough so that it won't kill me in a minor accident, but I still won't have the piece of mind until this shell is scrapped or fitted with a roll cage. I don't really have a strong method. It's just will power to keep this thing going.Question... if someone (me) was working on a 1996 one of these for a young enthusiast in my squadron, and was debating starting upgrades (either 3800 turbo or LS-swap) while the underbody looks just as crusty... is there a standard approach to reviving/protecting the unibody structure? It seems like surface rust more than the structural cancer my GTP chassis died of after 15yrs of NY/MI/WI/MN winter fun.
For the most part, my approach has been dealing with the worst parts first. If there's rot, there's no way around cutting it out until you find clean metal and welding a patch in. I've even cut pieces of the frame channels out and rebuilt them. Since my welding skills are meh and I had to cut almost the entire floor out of the car, I reinforced everything with weld in subframe connectors. In theory, it's not necessary but these cars are flimsy from the factory and these bars made me feel a lot better. I would not recommend anybody doing this sort of restoration though. Rust free V6 F-bodies are cheap. I only did all this work to prove to myself that I could and because I have an odd love for reviving unloved cars. There's also a lot of sentimental value in this particular car.
Other than that, it's really just staying on top of it as best as I can. Rusty bolt-on parts like suspension links are just fun opportunities to upgrade. However, I refuse to bolt a nice new part to rust. The suspension brackets are in good shape and easily cleaned up with a wire wheel and some chassis paint or Eastwood rust converter. Don't use rubber undercoating. Naval jelly also works well for cleaning stuff up and I don't use it as much as I should. Eventually everything that bolts to the shell will be replaced so that I don't have to worry about them. If I at least give each part of the shell that the parts bolt to a good repair then I shouldn't have to worry too much about the shell either.
Once I start creeping up to about 450hp, this shell is going to start giving me the creeps regardless. I have a plan for stiffening things up, but I may eventually move to a nicer chassis and tune this car back down.