This is a major project to do and if you have never done this kind of heavy structural work I would not recommend it. The car will need to be supported properly while the inner and outer rocker are cut out or the body will sag and nothing will fit. As far as your question about the reproduction rockers, I would assume the parts will need to be modified as with most reproduction parts. The reproduction parts have gotten better over the years so if yours are really old I would recommend buying a new set and see for comparison. Good luck to you.