Tire clearance

I have a 64 barrcuda with 8 3/4 rear end, 6 leaf springs 3in lift, stock spring location and stock shackles.
I'm looking to put 255/60/15 tires on 15x8 rims with a 4.50 backspace and 0 offset, do you think they will fit without any modifications?
Right now I have
225/70/14.
Thanks all for your input