You ask the question we all wish we could answer, whats it worth well its worth what you think you have into with parts and labor. I have no clue but looking at it I would say you are probably into that car for around $40-50K now I cant see the paint, engine detail and undercarage so I may be way off.
I think this car looks to be very clean and built well. I can see it going all over the place, problem is there are too many cars for sale right now. I have a nice 69 that one of my customers bought at BJ for $35K and then dropped another $45-50K in it and it has been for sale for almost a year now.
So the question is what is it worth. The one we have is worth around $80-90K to build again but we cant even get a $50K offer for it so the market is real soft right now on these cars.
I would hold off untill you have to sell it unless this guy comes up with a number that is to sweet to pass up. You know what you have in it and what you have to get out of it to make you happy. If you are not forced to sell it yet hold out and get his number and hopefully things will trun around for you.
The election is almost over and things will turn around for the better

The times always get tough when we go into an election year and hopefully you can hold it together so you can keep the car as it would be a shame to part with such a fun driving car.
Good luck