Please help small to big bolt pattern

Someone with the KH disks may correct me, but I don’t think there’s enough material to redrill the stock SBP KH disk hubs to LBP. If I remember right the hubs aren’t solid or the same thickness in the area the new bolt pattern would fall.

In the front you’d either need to do the Mustang rotor/hub swap to keep the KH set up. Or replace the KH’s with the later 73+ brakes, but that’s a spindle swap and all new brake hardware.