overhaul, and paint, and refurnish it completly
On line. Go to "Google" or any other site you want and type in "Replacement parts for a 1971..." Summit may be a good place to start. A local junk yard or even a far distant junk yard may hold 1971 Chevy parts, but be careful if thy are damaged, or deteriorated beyond use.
Search Chevrolet Impala Questions
Chevrolet Impala Experts
Related Models For Sale
Used Cars For Sale