12 bolt and 15x10s?

[slownova]

I have a 78 Malibu and I'm trying to put a 15x10 wheel with 28x10.5 tire. I'm using a 65-67 12 bolt rear end. What back spacing do I need? Searching didn't net much, but I saw a 15x8 works with 5.5 back spacing. Any help is huge. Thanks!!

 

[Bratly51]

That year 64-67 housing without a frame notch 5" bs, notched 5.5" bs.

Then 68-72 housing is a 6" without notch, 6.5 with.