Preheat the smoker to 250 degrees F. using hardwood lump charcoal (mesquite and hickory blend is what I prefer). If cooking in a conventional oven preheat the oven to 325 degrees F. and cook for 15 to 20 minutes per pound.
Bring the ham out of the icebox for about 1 hour before cooking to let it warm.
In a mixing bowl, combine the brown sugar, onion powder, cinnamon, chili powder and smoked paprika. Mix well.
Rub the ham on all sides with mixture. Place the ham on a smoker or hang with hooks on rebar. Or place in the conventional oven.
If smoking, to the coals add cherry or apple wood chunks the fire box and place lid on and cook for about 15 to 20 minutes a pound, or until the internal temp is 130-135 degrees F.
Remove the ham from the smoker and place on a cookie sheet. Take a knife and score the ham ½ -inch deep in a diamond pattern, on the top side of the ham.
In a saucepan over medium-low heat, pour in the whiskey and cola and bring to a simmer. Stir in the honey, brown sugar, cloves and butter. Bring to a low boil, reduce the heat and simmer for about 2 minutes.
Place the ham back on the smoker and brush about ¼ of the glaze over the ham. Cook for an additional 15 minutes, basting about every 5 minutes.
Use a culinary torch or propane torch to caramelize the top until the glaze begins to brown. If doing this in the conventional oven turn the oven to broil for about 6 to 8 minutes.
Remove the ham from the smoker and place on a baking dish. Cover with foil and let rest for about 10 minutes. Slice the ham against the grain and serve warm.