Will 275/60/15 rub with 10" wheels and stock suspension?

[2bits]

I have searched a bunch of topics but everyone drops their trucks these days and I want to zero in on what I am wanting to do. I have a 61 Short stepside, stock suspension and staying that way. I've got 15x10" slots and I would like to run 275/60 all the way around. I know the front will be fine but my worry is the offset of the deep slots might cause a rub on the rear.

I know that the offset will make all the difference... but I don't have it measured yet. My first thought was to just get an old junk 275/60 and just slap it on and see how it sits but wanted to know if anyone ran this setup: 100% stock suspension, stepside with deep 10's. Pics and info would be appreciated. Thanks.

This is the truck with some crap 295/50s on it to give you a feel for the wheel size.