I have done the conversion on my 240Z. I used the 240Z cables and modified them so that they would work. I had to drill a hole in the clevis on the cable and run a bolt through it to make it work. You may need to relocate the pivot point where the lever is connected to the cable to increase the movement. I don't know what calipers and other parts you are using so email me with a detailed description of your setup and I will try to give you an idea on how to make it work.
Ian