LS1 rear end measurment for brakes

[gearheads78]

I was told the measurement from the face of the axle housing flange to the face of the axle where the rotor sits is 2.770"

My Olds rear is 2.750" so the .020 should not make a difference. I am trying the put the rear brakes together right now and the caliper basket is way off center to the rotor. I need to know for sure what the LS1 factory rear measurment is so I can space the backplate out to make this work.