64-66 Dart GT Question - cat whiskers

I had a customer make a longer outer sweep for his 66 dart from a 70 challenger set. then he complained that it was scratching his SS divider post (I told him it would eventually rub scratches in it if he used it a lot.) I had to take the longer one off and replace it with the original one I was going to put back on until he insisted that it should be longer. I'll admit that I didn't think it would only take months to do that though, more like a year or so and that surprised me since catwhiskers are pretty soft.