Clearance for slicks

I'm looking at opening up the quarter panels for tire clearance. I want to make the opening so that it looks like a super stock hemi car in case i go to that large a slick. I do not know however which is the proper way to do this and still retail the look with the factory body lines around the quarter. Has anyone done this? What is the right way to do this so that it looks good and not like someone took a sawzall to it to open them up.