Nice project. I'm doing the same now and doing some massive suspension and brake upgrades to a 225 Scamp (there's a thread here in the restorations forum).
For the rear end, I was able to find a non-sure grip 8.75 with 2.76 gears for about $200. I went ahead and bought the Dr Diff brakes for the rear despite using Wilwood on the front. I liked the e-brake on the Dr Diff unit way better than the mini drum inside a rotor the others use. The rear was a b-body unit which is a couple inches longer and should help with the spacers/offset issue to utilize the newer style wheels.
Keep up the good work!
