17" Torque Thrusts on 68 Dodge Dart

Ok I want to put some 17"x7 or 17"x8's Torque Thrusts on my 68 Dodge Dart Convertible. I have 73 Disks up front, stock 8 3/4 with moser axles BBP. Wheel wells are not moved nor are the springs. Anybody know what backspacing I will need on the front and the rear? And if a 17x8 will fit on the back? Also what size tires will I need?