Floorboard bent up from forklift

[Gunfreak25]

This is my 54 GMC deuce, many years ago I was told it was a stripped down and gutted body/chassis and was picked up with a forklift which bent up the middle of the cab floor. It's a running driving complete truck now, but the bend is about 5 inches tall in the center. I'd like to get it down as it causes the passenger seats to tilt a bit and the Tcase & E brake lever to bind in their slots a little. It's very thin metal and I think it could be done with a hand winch from the bottom of the truck.
Any ideas? These pics are a week old and I have since then cleaned and power washed the entire truck, inside and out!

 

[ralbelt]

I'm thinking a bottle jack on the floor, pushing up against a 4x4 that protrudes thru the doors that is anchored down with chains around the chassis.