Stock '70 has four wheel manual drum brakes, manual steering, Dana 30 up front, no options that most people add. No rust is a good thing, blown motor is not. V8 vs. 6-cyl will make a difference. I'd say $1,000 - $3,000 if the body is straight and solid and in need of minimal work and a re-paint.
Pictures are worth 1,000 words.