kz1000 rear caliper question

hi i have a 77 650b that im setting up with arear disc, im using a 77\78 kz1000 spoked wheel, my question is what model\and years caliper is compatible with this rim, summers here and im getting tired of riding with just front brakes thanks-gorack:angry:

Here's a list of bikes that use that same caliper...

thanks sandy

Any time!