What is a fair price to ask for this car and how do I find this out?

its a 2 door???

Year Make Model Submodel Body Type Engine Average Value Trend 1971 Chevrolet Impala Convertible 8-cyl. 350cid/245hp 2bbl $15,982 Trend 1971 Chevrolet Impala Convertible 8-cyl. 454cid/365hp 4bbl $25,362 Trend 1971 Chevrolet Impala Sedan 8-cyl. 350cid/245hp 2bbl $6,315 Trend 1971 Chevrolet Impala Sport Coupe 8-cyl. 350cid/245hp 2bbl $9,488 Trend 1971 Chevrolet Impala Sport Coupe 8-cyl. 454cid/365hp 4bbl $13,152 Trend 1971 Chevrolet Impala Sport Sedan 8-cyl. 350cid/245hp 2bbl $8,168 Trend 1971 Chevrolet Impala Kingswood Station Wagon, 2-Seat 8- cyl. 350cid/245hp 2bbl $7,419 Trend

CarGurus has 53,183 nationwide Impala listings starting at $600.

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Yes, a 2 door.

To clarify- it is a 1971 Impala Custom Coupe 400 Turbo V-8 with 31,600 miles. Red 2 door with vinyl top. Has a few scratches on paint. Perfect black interior with air conditioning. Runs great. Where should I start with an asking price?

The 400 ci came in later years, but not in 1971. Since this is not an original engine, I'd start with a lower price of $3500? and see what he says. The 8 grand need to have prime paint, and everything there is top condition. It is a gas hog, burt gas was under a dollar in 71 also.