getting another block is a good idea, but considering where the crack is I would try to fix it. start by drilling a small hole (1/8 or 3/16) at each end of crack so it will stop spreading. grind out and fill with nickel rod or you could possibly braze it with a torch. just grind weld down flush with the block surface (check with a straight edge). just make sure weld is not sticking up. should be fine.