Set of tripple webbers on an original intake manifold will run you around 2 grand to start with if they're missing.
The only other real expensive bits to get hold of if their missing is the driving lights for the grill, big fuel tank (if it's missing).
Everything is relatively cheap and easy to get a hold of as far as I can remember.
Total resto cost is anyone's guess and depends on the condition of the car to start with...