Yes. The box shaft is different. It's a different size gear requiring a different Pitman arm.The Pitman arm from a 73 -76 will not work on a 67-72 power steering box and vice versa. Again, you want to use the steering box, Pitman Arm, Idler arm and drag link all together as a unit. Use either the 73-76 parts or the 68-72 parts. By the way, 67s have a unique one year only IDLER arm, but ..that's a whole 'nother subject.