Oh I thought you were talking about your Dart. On a Duster 255's are easy, 275's fit with the stock spring locations. I have 295's on my duster, but that's with a 1/2" spring offset and a quarter lip trim.
But, the axle center to the front bottom corner of the quarter measurement is the same, 14.5". I just checked my duster, which is 15", but I have oval track springs which have a 1/2" longer front section. So the axle is moved back the 1/2" you'd need to move yours.