We normally roast our chickens pretty simply, basted with butter and sometimes lemon juice as well.  Here is a roasting chart for stuffed whole chickens, at 325 degrees: (For unstuffed chicken, roast about ½ hour less)

4 – 6 1/2 lb. chicken — 2 ½ to 3 ½ hours.
6 ½ – 8 lb. chicken   —  3 ½ to 4 ½ hours.