L79 engine differences: 66-67 Nova

I remember very clearly one day at the drag strip more than 40 years ago. That day a 66 Acadian Sport Deluxe L79 went up against a 69 Z. They had 6or 7 shots that day and every time the Z was at least 6 car lenghts ahead. I was real disappointed as at the time the Acadian was the favored car.