I actually just finished rebuilding my uncle´s 71 Norton Commando 750. Hopefully your father´s bike was stored in a good facility so it won´t be in too bad of shape. You may want to figure out why your father stopped riding it in the first place before you consider working on it. If it was something major then it could end up costing you a bundle to repair it. The Norton was my third complete engine rebuild and i still foun it very challenging. Best of luck to you. Enjoy the experience.