Fattest Tire under a 73 Dart swinger

I think you could if you rolled the lip on wheel well I have a 255/60 on mine with the 4.75 back spacing and theres actually more tire clearance on wheel well lip than the leaf spring Easiest way is to get the rim and go buy a used cheap tire in the size you want and try it out on both sides

What width of wheel are you running with the 4.75 backspacing? It might make a difference depending if they are 7's or 8's.