Pour chocolate syrup into 12-cup fluted tube pan sprayed with cooking spray.
Beat cake mix, water, oil and 3 eggs with mixer until blended.
Add sour cream; mix well.
Pour over syrup in pan.
Beat cream cheese and sugar with mixer until blended.
Add remaining eggs; mix well. Blend in evaporated milk and melted chocolate; gently spoon over cake batter in pan. Cover with foil sprayed with cooking spray, sprayed side down.
Place tube pan in large shallow pan.
Add enough water to larger pan to come at least 2 inches up side of tube pan.
Bake 1 hour 30 min. or until toothpick inserted near center comes out clean. Cool completely in pan. Refrigerate 2 hours. Invert cake onto plate; remove pan.