Okay. I found some larger fender pieces that already have flares in them here http://www.showcars-bodyparts.com/240z.html. Scroll down to see pics of the 4 inch fender flares. I think they are fiberglass though and not metal. I wanted to find some metal replacement fenders and bolt on the fronts, and weld in the rears. I'm thinking they don't exist...
Edit: I don't think they are letting me post links yet since I am so new. The website is www. showcars-bodyparts dot com/240z.html.