Place pecans in a 13x9x2-inch baking pan; heat in a 250° F. oven 5 minutes. Melt butter in 2-quart saucepan over medium heat; stir in corn syrup and half the sugar. Bring to boil, stirring constantly then boil without stirring 5 minutes. Pour syrup over nuts, stirring constantly to coat evenly.
Bake in 250° F. oven 1 hour, stirring several times. Sprinkle nuts with remaining 1/4 cup sugar, tossing to coat evenly; immediately spread out on greased cookie sheets to cool. Quickly separate into individual pecan halves; cool. Store in tightly covered container.