I've been doing the same for my '81 Trans Am. I hope to finish the passenger floor today. I looked all around for floor sections like what you got and settled on getting them from Summit Racing because I was driving close to their Texas store while on a road trip. Only using portions of each to replace only the small areas of rot in my floor. Heat rising from my headers and exhaust is what caused most of the floor damage.
Thanks for watching . I had another pan in the rear that only need patches. I cut most of the old pan out to place the new one in as i didn't want to just patch and over lap too much. This gets rid of most of the rust so that pan will hopefully not need to be done again
