Sale Price for 1926 or '27 Model T Parts

Hello folks. My Dad has a '26 or '27 Model T sitting in the backyard. It's not complete - it has the chassis, transmission, radiator, rear end & engine. I would say it's in poor condition as it's been outside for over 70 years. Someone has offered to buy it. What is a fair price for my Dad to ask? Thanks in advance for the advice.