Roasting temperature: 325 degrees
Test the final internal temperature with a meat thermometer inserted into the innermost part of the thigh, not by looking at the clock. The internal temperature should fall between 170 to 180 degrees, or else poke the bird with a knife to see if the juices run clear.

UNSTUFFED WEIGHT ROASTING TIME
8 to 12 pounds: 2 & 3/4 to 3 hours
12 to 14 pounds: 3 to 3 & 3/4 hours
14 to 18 pounds: 3 & 3/4 to 4 & 1/4 hours
18 to 20 pounds: 4 & 1/4 to 4.5 hours
20 to 24 pounds: 4.5 to 5 hours

STUFFED WEIGHT ROASTING TIME
8 to 12 pounds: 3 to 3.5 hours
12 to 14 pounds: 3.5 to 4 hours
14 to 18 pounds: 4 to 4 & 1/4 hours
18 to 20 pounds: 4 & 1/4 to 4 & 3/4hours
20 to 24 pounds: 4 & 3/4 to 5 & 1/4 hours

Source: Latimes.com

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