Roasts normally require 1.5 hours of smoking time per pound of meat. A roast isn't fully cooked, however, until it reaches an internal temperature of at least 190 F.
Because smoking uses comparatively low temperatures to baking, internal temperature is a more reliable measurement than time. Small pieces of meat, like chicken thighs, might only take 1.5 to two hours while large pieces of meat might take four to six hours.
The U.S. Department of Food and Health Services maintains a list of safe minimum cooking temperatures for many meats. Most meats fall within a range of 140 F to 165 F, however some recipes may call for higher internal temperatures.