You could sell it and put the $ toward the other cars.
Probably $25-30k at least to restore that car (maybe more or less depending on how much work can be done by the owner versus a shop).
I think if one had a shop do the whole resto, added costs would exceed $30K easily. I had figured a minimum of $20K with me doing the bulk of the work (I usually farm out the engine and tranny rebuilds and things of that nature). Either scenario should still yield a completed project cost that remains in the black...assuming that one is concerned with that aspect. Sometimes we build these cars out of love and enjoyment and not the bottom line