According to the pilot of the tailwheel-equipped airplane, after performing an initial test flight, during the landing roll the airplane rapidly veered right and the left wing struck the ground. The pilot reported that he overcorrected by applying full left rudder and the airplane exited the left side of the runway and nosed over. The pilot affirmed that prior to the flight he performed maintenance on the airplane to include the tail wheel single bungee steering system. The pilot reported that he installed the bungee incorrectly. The airplane sustained substantial both wings, the windshield and the fuselage.