The 67-9 Valiant started the evolution into the Duster for 70 and has the same body lines from the door forward and still has a 108 wheelbase and dash like the 67-9 Valiant. I haven't compared the wheel wells between the two but I have had 275/60/15's on one of my 67's before and I have 255/60/15's on the rear of my 67 now with plenty of room. The Dart is 111" wheel base so it is 3" longer.