[Blown353]

I would run an 11" wheel personally; there is plenty of room and the wider the wheel the stiffer the sidewall will be.

315/35 on a 17 x 11 is right at the limit for a 68-72 A-body so you have to take very careful measurements.

You need to get the backspacing perfect. You may also have to trim the lip, and depending on how low your car is it may very well rub the reinforcement rib in the outer wheelhouse located above the fender lip-- that's where the clearance problem is on my car. I had to drop back to 285/40 on my 11" wheels because of the clearance issue with the outer wheelhouse reinforcement.

Depending on your brake configuration with a stock-width rear end you'll probably need between 6" and 6.5" of backspacing to get an 11" wheel with a 315/35 to fit. Most guys seem to end up with 6.25"; I ended up with 6.5" because of the extra thick aluminum hats on my 2-piece Baer rotors.

Remember, if there is any doubt on outer lip clearance always order the wheel with a little more backspacing; that can be easily corrected with a small spacer. Not enough backspacing and you'll be ordering new wheels.

There is a big wheel & tire database thread over in the wheels & tires section at Chevelles.com I suggest you browse through.