Depends on a lot more than you've given us. As noted, the correct engine, tranny, and rear are important, as are what options were on the car but need to be reacquired. For instance, putting a power steering set up back togethor costs a chunk, as does putting a missing shaker back on. Basic items like carb, distributor, and rev limiter also will set you back a couple of hndred dollars each. Conversely, if it has the shaker, or other options like a 4.30 rear (aka "Drag Pak"), deluxe interior, tach dash, etc., the value goes up.
Give us more info, and we'll try to help . . .
Carl