Finally broke down and ordered a rear floor pan for my custom 300. It arrived Saturday and it is a very good looking piece. It is a heavy gauge metal and laying it over the existing floor it fits perfectly. it is larger than I will need but I haven't had time to figure out where to start cutting yet. But I am very pleased with it , it is made by EMS.
I was pleased with the fit of the floor pans I purchased from EMS. I didn't trim the first one I installed and had to slightly massage some of the lines. I did notice that installing the pan untrimmed, the rear edge fell almost in line with the floor support. I had to remove and re-weld the rear seat hold down and with the seam nearly in-line with the floor support, I was unable to dress the weld on the underside. The EMS panels are great and the problems I encountered were of my own making!
Well I finally got my EMS rear floor pan in last week. After much crawling in and out ,measuring ,pecking on the floor to find and rusty areas I marked my new pan and cut it down and then marked my floor and cut it out. I left the new pan a little large to begin with and trimmed it down a little at the time. Finally I had the new pan where it would just barely fall thru the floor. we wanted to butt weld as much as possible and needed a very small space between the old and new sections. My good friend Bob who has a hotrod shop near by owed me some labor and did the welding for free ,he did a very good job. I did a little cleanup on the welds , seam sealed ,primed and painted the new section. I still have some work to do on the underside ,I plan to clean and paint the entire floor that will be a lot of cleaning. I could not be happier with the EMS quality ,and I highly recommend them.