The series is currently undergoing an unprecedented overseas engine test programme as it looks to quash any remaining concerns over parity with the Gen3 cars.

The testing – which is taking place at AVL in Detroit – has been split into two phases, one to understand the facility and the engines, before a second to tune and determine parity.

Phase 1 was successfully completed last weekend with Supercars and manufacturer representatives returning to Australia on Monday.

Phase 2 was set to begin next week, however Supercars has now decided to push it back to later this month so that the data collected from the first phase can be properly assessed.

“Phase 1 of our testing at AVL has gone very well,” said Supercars CEO Shane Howard.

“The GM and Ford units have been thoroughly tested, providing us with valuable data to compare and analyse.

“We’ve had great support from both Ford and GM, which has helped us to navigate some slight challenges successfully.

“There is a heap of data we are collectively now working through, and we all agreed that to ensure we put the best possible test plan together for phase two, the best option is to push back the original schedule slightly.

“Once testing is completed, information from the AVL testing will be passed on to all teams accordingly.”

It is hoped that any changes required to the engines can be made before the Bathurst 1000 in October.