Help please. How much is this worth??

My girlfriends dad has a Mopar 340 block that he asked me to help him sell. Has main caps, crank, pistons, 7 connecting rods, and he said something about needing a sleeve. If I remember right the casting number is 2780930. He bought this about 15 years ago for his duster and really doesnt know how much it would be worth today. Any help appreciated. Thanks.