Hard to pin down a value on any particular car, especially rarer cars due to an almost infinite number of variables, including those not related to the car itself, i.e. overall economic conditions.
If you look at auction results history for the last several years on 69 COPO Camaros that
sold, a general range is about $160K to $200K. There are certainly flyers that exceeded $250K, and a few that were in the $120 to $140K range.
Auction results are not a perfect gauge for value, but they do reflect what someone did actually pay for a car (unless the owner bought their own car back, which has happened with no reserve auctions).
Pick a number you'll be very happy with and list it on SYC! The actual market will be in touch with you through your PM's