Section width is the width of the body of the tire, the bulge if you would, generally it is 1.5-2.0 wider than the thread. I am assuming you have L60s which are wider than the 275s, probably closer to a 295 but I don't know of a 295 60, there is still a 295 65 but it is tall and wide and looks really awesome on 68-69 B bodies. Rim back space would be the key to making them work on an E body. I have a 255 70 15 on a rim on an S-10 chassis I have and I cant really see it on a car, not sure it would look right.