US round of Intercontinental GT Challenge set to be six-hour race

The event, which will share the bill at Austin next March with the Pirelli World Challenge, was by Stephane Ratel last month, but the series boss now believes it should be of longer duration.

The change has been designed to make the fixture more attractive to European GT3 teams.

"To help to convince people to come from Europe we need the tried and tested format of two stints each for three drivers, so that makes six hours, although we are also looking at five," Ratel told Autosport.

He revealed that the target entry for the race was 30 cars.

"If we can have 15 cars from Europe and 15 from the USA, then it will be a success," he explained.

"It is not going to be huge in the first year, but 30 cars is enough to make a good race."

Ratel believes that the race will be attractive to both European and US teams because of its timing in the season.

PWC vice-president Greg Gill expressed confidence in 15 entries being able to be found from North America.

"We have made a commitment for 15 cars and we believe that we have a good chance of achieving that, although I can't tell you that we have 15 entries right now," he said.

He revealed that many PWC teams owned the equipment necessary for endurance racing and some had additional cars.

The race falls two weeks before the Sebring 12 Hours round of the renamed IMSA SportsCar Series, whose GT Daytona class will be run for FIA-spec GT3 cars from next season.

Ratel revealed he hoped the Austin event would be sponsored by watchmaker Blancpain, which backs his endurance and sprint series in Europe, and suggested the Blancpain 6 Hours of America as a possible title for the event.

Plans for a crossover between the Blancpain Sprint Series and the PWC have been abandoned, Ratel stated.

It was planned that the first three cars from the PWC would be invited to take part in this year's BSS finale with the top three from Europe going to the North American series for its season opener.