I just now discovered that the other side of that frame rail has a hole the size of my fist rotted through it. The floors are prefect, because the previous owner coated the entire interior in dynamat and POR15. However, the running rails under the floorboards are rusted at the front, and have major holes in them as well.
I'm seriously considering getting another rust-free body and building a car from the ground up. I just don't have the time, money, or resources to complete such a task right now. Simply cutting out the rust on the frame rails and patching or boxing a new one on simply isn't going to cut the mustard.
If anything, I will spend the next few months stripping the car and salvaging what I can from it. The engine is completely rebuilt and has a bigger camshaft, it runs mint. As long as I can find another '77 280Z body in better condition I can build another car from the ground up, it's an intimidating task, but there's nothing stopping me from doing it (besides money, and lack of a garage of course)
I just hate to have to cut the car up and part it out. The 77 280Z is essentially my dream car, I should have looked closer at the rails and frame before I bought the car. Lesson learned for sure.