Preheat the oven to 325 degrees. Score the ham about 1/8 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 1/2 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 1/2 hours of baking time, brush glaze over ham and return to oven, repeating several times until ham reaches 160 degrees.