CYLINDER HEAD VALVE GUIDES WORN REQUIRING REPLACEMENT BEFORE WARRANTY EXPIRATION. IF NOT REPAIRED CATASTROPHIC MOTOR FAILURE CAN OCCUR. IF THIS HAPPENS CAR BECOMES UNCONTROLLABLE WITH OIL AND COOLANT FLOODING OUT OF MOTOR. NEW HEADS WERE ORDERED FROM THE FACTORY AND THEY WERE OUT OF SPECIFICATION AND NEEDED MODIFICATION BEFORE INSTALLED. PREVIOUS 2008 CORVETTE (UNKNOWN VIN BUT CAN BE FOUND AT DEALERSHIP WHERE SERVICED HAD THIS SAME PROBLEM LEADING TO THE ABOVE MENTIONED FAILURE AND UNCONTROLLED VEHICLE CONDITION. THIS HAPPENED ON AN OFFLOAD VENUE SO THERE WAS NO ACCIDENT REPORT. I DON NOT KNOW THE EXACT DATES BUT ENTERED A DATE AS REQUIRED BELOW.