Small update, but one of particular interest to kz750 twin owners.
I was cross referencing part numbers and realized the z1/kz1000 share the same head studs as the KZ750 twin. This means you can use APE's heavy duty head studs and nuts which are intended for the z1/KZ1000. I have bought a set and can now confirm, however, you do end up with 4 extra studs and nuts you don't need. These bikes are notorious for head gasket leaks, increased compression will likely make this worse, hopefully this will help address that.
I was cross referencing part numbers and realized the z1/kz1000 share the same head studs as the KZ750 twin. This means you can use APE's heavy duty head studs and nuts which are intended for the z1/KZ1000. I have bought a set and can now confirm, however, you do end up with 4 extra studs and nuts you don't need. These bikes are notorious for head gasket leaks, increased compression will likely make this worse, hopefully this will help address that.