Triple Eight has pointed the finger at Supercars over the recent lack of speed of the Ford Mustang driven by Will Brown, and Supercars has admitted that a part it supplied to the team was undersized.

On Wednesday afternoon Triple Eight team principal and co-owner Jamie Whincup issued a statement in which he revealed that an engine air restrictor, a part Supercars stipulates all the Ford engines must run, was the wrong size.

“At 7pm last night we found a significant issue on car #888,” said the statement.

“Since the start of this season, car #888 has been running with an undersized engine airflow restrictor. This