Using air hammers to take cars apart will cause some damage to the chassis-bent flanges and stuff like that. Here, Inman used a body hammer and railroad dolly to straighten the framerail flange edge under the Mustang's floorpan. A new floor will be welded to it soon. This is also a good time to run a grinder across the edges of all the panels. It's hard to weld to a rusty panel, and you don't want to trap rust behind your new sheetmetal.