Need a body measurement... 31 Chevy 4 door

Hey guys Im in a bind and need to get one measurement to get me started. I have a floorless 1931 Chevy 4 door body that I need to make a new sub floor for. The only thing I can see to work off of is the B pillar floor mount brackets. I need a measurement from the inside tip to tip of this across the floor. Anyone able to help me out? Man I'm used to the fords where at least there is some metal on the floor to work with. :LOL:

Thanks for any help or other measurements I might be able to use.

http://i52.photobucket.com/albums/g2...Untitled-2.jpg

http://i52.photobucket.com/albums/g2...n/Untitled.jpg

You're showing pics of the area needed for measurements. Don't want to sound stupid here but is there a reason you can't take a tape measure and just get the measurements?
When I do mock up for any metal work, I always start with cardboard. Make the floors out of cardboard and then you have something to measure, cut and fit .