Welcome Union Bubba,,, I had a rear seat out of a 96 CC in my 66 F250,,, the seat rails are the same width,, the difference is the studs, I heated them up on the 96 and popped em out and then used a piece of 1 1/2"x 1 1/2" square stock as a spacer between the seat and the rail, because my seat adjustet would hit it,, not sure on the 78's but it also gained me a better seat position anyways. I really thought that was awesome on mine,,, 30 years later, and still the same rail width,, cool.