Roughly chop 4 cups pecans in a food processor. Remove 2 cups and reserve. Finely grind the remaining pecans in the food processor.
Combine the finely ground pecans, vanilla wafers, confectioners' sugar, bourbon, and corn syrup. Coat finger tips with the softened butter to help you roll. Shape the mixture into balls 1 1/2-inches in diameter using an ice cream scoop. Roll the balls in chopped pecans.
Arrange the balls on a dessert platter. If the balls are too soft, chill (about 2 hours) in the refrigerator to help firm, if desired and serve.