Need help to ID my 8 3/4 rear.

I need a little help, I am still checking the car out and I'm in the discovery phase with my new Dart. I took some measurements today and did a little investigating. I think the rear end is an 8 3/4 out of an A-body. I measured from the surface of the drum to the leafs, I came up with 5 7/8". I was not able to measure the total width since it was just me in the garage and my arms are not that long. Does anyone know if this is an A-body rear. The guy I bought it from told me it was from a Valiant, but I thought that Valiants did not come with 8 3/4.