The most convenient driveshaft to use is one from a Vega, any year. This will bolt right up to your rear end yoke and slip into the tranny. You can also use a stock driveshaft from a 70-81 Camaro or Firebird. This is 3" shorter than the stock Nova one but will require an adapter u-joint in the rear. You can get these u-joints from most auto parts stores.