Aston Martin still unhappy with World Endurance GTE Pro BoP

Aston Martin Racing boss John Gaw pointed out that the increase in air-restrictor diameter for his Vantage GTEs equated to only 40 per cent of what they have lost over the second half of the WEC and that the weight increase for the Porsche 911 RSR added up to only 50 per cent of its reduction ahead of the Nurburgring round.

"It's not going to close the gap completely, but of course it is going to help," he told AUTOSPORT.

"It is still going to be tough for us because we haven't got back everything that we lost.

"But the good thing about this is that the rulemakers have acknowledged that they have made a mistake and moved to rectify it."

Gaw has previously described the Spa BoP as "the most equal in the history of the WEC".

The changes have come after the factory Manthey Porsches notched up one-two results in class at both the Nurburgring and Austin WEC rounds in August and September respectively.

The best-placed Aston finished fourth each time.

The Vantage's air-restrictor has been increased 0.2mm in diameter over the 28.6mm it had to run at the Nurburgring and Austin, but that is still 0.3mm down on the 29.1mm orifice it ran at the first two rounds of this year's WEC.

The Porsche's 10kg weight break has been reduced to 5kg, meaning it is now running at 1220kg.

The Ferrari 458 Italia's BoP is unchanged since Spa.

There is a separate BoP for the unique demands of the Circuit de la Sarthe at Le Mans.