Tire suggestions for '74 Dart Swinger

235-45-17 up front--no clearance problem.
245-45-18 out back.

Hi, What backspacing are you running on those rims? I'm in the process of converting my 69 Swinger 340 to 4.5 bolt spacing and I am trying (like all of us I'm sure) to fit the biggest rubber front and rear (without mods) without rubbing issues. Any help would be appreciated.