Value of a stock 306 bottom end? please input

[1990 HOSS]

I have a 306 motor that a guy is interested in and he is willing to pull it out of my wrecked car. He only wants the bottom end (which is rebuilt, not forged, and has about 50k miles on it). I'm gonna keep the gt40 heads and edelbrock intake. How much do I ask for it, being fair to him and myself? Thanks for your input.