I own a high end restoration shop so that is not an issue at all. However and that being said, my time is worth money so I have to keep that in mind in the overall picture of the restoration. I am thinking very easily $100-125,000 including parts and labor for the restoration back to concours correct and that makes me VERY nervous especially with a non original short block.
Rick consider this, most cars don't have their original motor.
Many were blown up back in the day and replaced. That's what happens when they are driven.
This can/may be a contentious issue for a buyer.
Your motivation is a key factor. If you are looking to restore/drive the car, how can you put a price on that?
Obviously you don't want to be upside down in it, but sounds like you are well aware of the costs.
Lastly, most would agree that auctions are NOT the best indicator of current values.
Chris