Randy,
This is my opinion only but race cars are a little hard to sell especially tubbed because the audience is not as big as selling street cars. Although it looks like your car could be a pro street car from the pics. Not knowing what all your car still needs to finish it's still a Firebird. I think if you find the right guy you should expect anywhere from 5 to 7,000.00 easy.
Again my opinion only. Curious to see what other guys say. I'd love to see that in my garage.
Good luck with the sale