The linkage itself is pretty easy. Basically, you take the "arm" off your old throttle body, its the part with the ball end on it, dont know what its real name is Then you take the 240sx linkage off, leaving the inner spring on the 240sx TB. Put the "arm" off the 280zx throttle body and put it on in the correct direction and then bolt it down. If the 240sx throttle body is one with cruise control, you will have to make a spacer for the shaft, or better yet thread it down far enough and cut off the excess. Here is a crappy, I just ran out in the garage and snapped a pic, picture. HTH
~Kenny