Widest 15" wheel combo for stock 65 barracuda?

What's the widest wheel & tire I can put in the back of a 65 barracuda, small bolt pattern? I have 15"x 8" cragars w/ 245/60-15's that are approx 10.25" wide, inflated on rim. Can't remember the back spacing, but it was standard from cragar.

If your car is restored I personally wouldn't go any wider due to rock chips to your rear quarter panel.