15" wheel question

Will 15" wheels with a 3 1/2" backspace fit on my 1964 Signet without modifications? It also has 73 Duster front discs and an 8.75 rear.

I've had 14's on it for over 25 years with 245/60's on the rear and 205/ 70's on the front.

My head is so spaced these days that I almost cannot think for myself, so I must thank you first for your answers