I am looking for the widest possible tires for my stock 70 Nova for front and rear without ANY rubbing issues. I have 15"x7" w/ 4.5" backspacing wheels for the front and 15"x8" w/ 4.5" backspacing wheels for the rear. I'm thinking about 225/60's for the front and 255/60's for the rear??? Any help would be appreciated.

Welcome to the site Paul. Can't help you with tire sizes on your 70, but that combo will fit on my 77.

Go to
www.2quicknovas.com
they have a lot of info on this subject.
Later

You can run a 15 x 8 rim with a 28 x 10.5 x 15 M/T ET Drag, a 28 x 12.5 x 15 ET Street or a 275/60/15 radial on the rear. You'll need to roll the outer lip and "clearance" the inner wheelhouse to fit em. A 255/60/15 is about 1" shorter in diameter than the 275/60/15.

On the front, I couldn't tell ya there. I run a 15 x 6 with a 205/70/15 and she works fine!

Derek