I'm doing a 65 Barracuda. I have been doing a lot of researching and accumulating parts for over two years before I started the project. I don't remember seeing items like after market door skins and rockers. ( if I'm wrong someone will chime in) There are nice floors pans and full floors available. I've seen serviceable door assemblies, hoods, fenders, rockers, quarters and chrome for 65 Barracudas. Bottom line...yes, there is enough stuff out there to do your restoration.
