This picture is believed to be from the 1966 IHRA Finals held at Green Valley Raceway on September 3, 4 & 5, 1966.
This car is certainly a carryover. At the time of this photograph the quarter windows and side scoops to create a fake GT350 would not have been available to the public. So this car must be a real 1966 GT350. And the lack of backup lights makes it a carryover. Plus the fact that the regular production 1966 GT350s had not shipped yet.
Our research indicates that this car may be 6S173, 6S186, 6S209 or 6S217.