Hey batman, don't freak out, a reed cage like that will go into the ZX, you get a mount block with it so the cage doesn't sink into the crankcase. The cage goes into the mount block and the block bolts onto the crankcase where your existing reed block goes.
Sorry if I am a little late with this, but I have had other distractions, car, bikes, washing machine. To quote a famous singer, "life is what happens while you're busy making other plans".