Finished tearing the floor out of the 71 challenger. I dropped the new AMD floor pan in and was actually pretty surprised at how well it fit around the perimeter. The sides and front are pretty good matches.
The bad news was that the transmission tunnel sits a good inch (maybe even a bit more) above the crossmember. It's also about this high at the firewall, but only at the transmission tunnel. The front footwells match the firewall well. I'm going to try and start pulling it down in the middle and working it out to the sides.
Has anyone else run into this with AMD metal? I'm going to try and snap a few pictures this morning to add as a visual.