Ignore what I said, I was thinking about V8, they have a big thick cone shaped washer on the end of the cable.

You adjust the clutch fork pivot ball with the box out, and with the bellhouisng attached to the engine and all the clutch hooked up and working. It is a threaded rod with a ball on the end with a locknut on the shaft that locks it in place. If you have just changed the cable this probably won't be your problem though, but it may have already been there if other adjustments fail.