The fenders from a 67-68 Chevy or 67-72 GMC will work but the problem you will have is that the 71 Chevy grill won't work with those fenders, at least not without modification.
67 Chevy & GMC
68 Chevy & 68-72 GMC
69-72 Chevy
Notice that there is no ridge on the 67 Chevy/GMC fender and that there is a ridge on the front of the 69-72 Chevy fender that the other members mentioned.