Biggest Rear tire setup on stock 68 dart 14" wheel

Don't know about width but the tallest tire I could find that was sanely priced was a set of 215/75/14's from hankooks for $69 a piece. They fit my Dart fine with the SS springs. I think theyd clear with stock springs so long as they arent sagged like mine was.

Edit: your wheelwells should be identical to mine in dimensions.