WHILE TRAVELING AT APPROX. 25 MPH DRIVER PROCEEDED TO MAKE A RIGHT HAND TURN WHEN IN THE CURVE VEHICLE SUDDENLY LOST ALL POWER. ENGINE QUIT, DRIVER HAD NO CONTROL OVER STEERING OR BRAKES. ACCIDENT OCCURRED STRIKING TWO VEHICLES. 2 CARS DETERMINED TO BE TOTALLED, 3RD CAR BEING EVALUATED FOR LOSS. OUTDOOR TEMPS WERE NOTED TO BE IN HIGH NINETY'S TO LOW 100'S. CAUSE OF ENGINE SHUT DOWN UNKNOWN AT THIS TIME, BUT POSSIBLE VAPOR LOCK PROBLEM MAY HAVE EXISTED.