I don't think it would work as is. My 74 mh is only 92 1/2" inside, pretty narrow for a car. The floor and frame are really not substantial, no place for tie downs. They are monocoque construction. 2000 lbs is a lot of weight for these, even with the interior stripped and you are going to have tools, spares, etc. if you are racing.
If you really want to do it I would start looking for one with a bad frame. There are some that have sat for years and the steel is wasted
(check this link). Build a frame suitable for the weight you will haul and put the body on it. This will also give you a chance to design a suitable structure to support the ramp and door.
John