I just happened on to this post by accident, so I registered today. It is like I am looking at my truck, an exact replica of what my truck used to be, two tone powder blue/white 4 speed stick shift with a 307 CID. My patch panel for the passenger side will be much like yours and the A pillar has the same rust. Thinking the rust is from the hole for the antenna wire going through the cowl/firewall. My cowl air boxes had years of hay and dirt in them which plugged the drain and allowed them to rust through. I remember as a kid when the floor was muddy it got the hose, which rotted the floor pan. Luckily my damage to the floor was not as extensive as yours, mostly next to the kick panels. If you have anymore pictures of your rocker panels during the install I love to see them. Is there a way to PM them and not to clutter up your post? I am having a difficult time getting my rocker panels to match the original body curve and seeing what you had to do would help I'm sure. Hoping my work looks 1/2 as good as yours!