5/7 static drop on a 79 1/2 ton will it rub?

[Mtrhd329]

I am looking at putting a 5/7 drop on my 79 1/2 ton stepside. currently I am running with a PO budget drop that looks to be maybe cut coils and leafs removed. I have 15x8's and 295/65/15's and was wondering if I will rub with a drop that low. Also will i have to notch the bed. i have seen some trucks with a 7" on the rear using a flip kit and shackles that shaved the bumpstops and had adequate clearance.