Trying to Decide Value of my 1969 Z/28

[danachevroletfor1967]

After much work and effort I have been told by my mechanic that my '69 Z needs a complete engine rebuild. There is too much exhaust smoke, oil getting into the intake runners, and the engine cannot hold vacuum at idle, it dies. Distributor has been gone thru, new valve seals, carb work, and intake manifold resealed. No external vacuum leaks can be found. Car has 80,000 miles on original engine that nothing has ever been done to, as far as I know. I can't afford a complete engine rebuild so have decided to sell it. I've owned it for 19 years and maybe it is time to pass it on to someone else to enjoy. I know what I would ask if the engine was fine but have no idea about the value knowing the engine needs to be rebuilt.
Here are some details on the car:

Original engine and rear end, trans is not original.
All sheet metal is original as far as I know.
Car was repainted in original Fathom Green more than 20 years ago. Paint is still excellent.
I have original Protect-o-Plate and Chassis Broadcast copy and owner's manual, along with pictures of the car when it was only 2 months old from the original owner.
Original black and gold California license plates. Period correct, although not original to car, dealership license plate frames.
First aid kit from dealership.
Five correct date coded YH wheels and 5 reproduction E-70-15 Goodyear Wide Tread GT tires.
Interior is in great shape.
Everything works except clock, fan blower motor, low fuel indicator light, and headlight washers (it is a Rally Sport also).
I also have that would be included with the car:
new OEM style restoration radiator and mounting hardware, new Holley 4053 DZ carb, and new OER fan shroud and mounting hardware.

How much might my car be worth? I know it is hard to come up with a value without seeing the actual car, but I would appreciate any help you guys could give me. I am going to try to add some pics with this post if I can decipher how. Thanks again guys.