I have a 1970 Dodge Super Bee. Appraisal advice?

I inherited a 1970 Dodge Super Bee. It is a 440 Magnum six pack 3-2BBL 390hp V8 Engine (automatic.) It is a 2-tone car - black hard top, silver body and was painted panther pink. I don't have the numbers matching motor and the car is in fair condition. I am ready to sell the car and I want to know how much it is worth. My dad said it was "one of 20." I don't know if that means it is 1 of 20 manufactured or is 1 of 20 still around. Any advice is greatly appreciated. Thank you!