They raised the roofline in 1964 when they did away with the unibody.
In 1965 the 223 6 and 292 Y block went away in favor of the 240 6 and the 352 FE engine. The floor and door sills and cab mounts changed as well. And of course the single beam front axle went away in favor of the Twin I Beam. So quite frankly you would be looking at a whole new tool.