The next-gen Chevrolet Camaro and Ford Mustang were expected to take part in what will be an all-in pre-season test for the six Melbourne-based teams and Brad Jones Racing from Albury.
The test would have marked the first time the cars have been run in anger outside of Queensland Raceway, apart from a handful of demonstration laps at Mount Panorama when they were publicly unveiled.
Garth Tander was set to drive the Chevy and Tony D’Alberto the Ford.
However that plan has been shelved, the cars remaining in Queensland at Triple Eight (Chevy) and Dick Johnson Racing (Ford) rather than travelling south.
According to Supercars, the Winton test was called off so that the Auto Gear Shift systems could be removed from the cars and replaced with the same mechanical stick shift used in the current cars.
That follows recent news that a proposed move to paddle shift has been formally scrapped.
Motorsport.com sources have also indicated that other changes, particularly in the area of ergonomics, are being looked at.
It’s been heavily rumoured that taller drivers are struggling to comfortably fit in the Gen3 prototypes.
“It’s in the best interest of the overall programme to take the prototypes off track and make changes to the manual gear change mechanism and respective ergonomics at this time,” said Supercars’ Head of Motorsport Adrian Burgess in a statement.
“It will be an exciting development for the programme ahead of our next phase of testing.”