Until I retire, I leave it up to customers to come and cut items out that I cannot unbolt, unless it is a very small easy to get to item. I watched 2 men come with an acetylene torch and zawsaw and work put more effort into it than I have to exert in order to get an entire front clip off, and it took them 3 hrs and god knows how many blades and other materials they went thru. It was a very good lesson for me as it reminded me why for now I don't get into cutting out big pieces of the car body carcass.
. If I understand you correct you have cut out too much that the standard pans offered by the two main companies listed below on our parts supplier page cannot help you out:
Classic Fabrications - www.classicfabrication.com
sheet metal, body panels, trunk, floor board, etc
Surfside Beach, SC 29575, 843-650-0385
I will probably have the 64 CDV ready to go by end of the month. Once I have it completely stripped you would be welcome to come down and cut out what you need at a very reasonable price. I have removed the front clip and will hit the interior by next weekend and should have some idea of the floor board. You have a 75 series but would assume the front section under driver and passenger would be the same or similar to the 62 & 63 series body styles. Russ may be able to confirm as I believe he has cut out pieces from these cars.
I do know that the Commercial Chassis is different. Not sure about the series 75. The one I did was a rust bucket also.
Original Parts Group is selling these brand new now, Just bought one for my 64 for 100 bucks