Well after measuring roughly with a tape measure it appears that the 280 strut tube is about 1-1.5 inches taller than the 240. If you used the 280 strut mount isolator it is also 3/4 or 1 inch taller than the 240 isolator. The rest of that extra height may be attributed to lower profile tires stiffer springs and struts vs. the worn out ones. and a lighter car sitting on those stiffer components isnt going to compress them much. Maybe some other guys will chime in with some better news.