Preheat the oven to 325°F. Score the ham about ⅛ deep on the diagonal in both directions to form a diamond shaped pattern. Place cloves where the cuts intersect. Place the ham in a large foil lined roasting pan with a rack and bake for 1 ½ hours. Meanwhile, make the glaze. In a small saucepan, whisk together brown sugar, mustard, vinegar and cola until mixture is bubbly. Cook on medium-high heat until glaze has thickened (about 15 minutes, or longer if needed). After 1 ½ hours of baking time, brush glaze over ham and return to oven, repeating several times until ham reaches 160°F.