Preheat oven to 350.
Grease a 9x13 baking dish. Set aside.
In a large bowl, combine pumpkin, evaporated milk, eggs, sugar, and cinnamon.
Mix until blended.
Pour/spread mixture into prepared baking dish.
Evenly sprinkle cake mix over the top of the batter.
Sprinkle pecans over the cake mix.
Pour melted butter over the top of the other ingredients.
Bake 50 minutes.
Allow to cool before cutting.
Garnish with whipped topping.