From this weekend's Sydney SuperNight onwards the Ford engines will be fitted with an 80 millimetre throttle body, which replaces the 87 millimetre unit that has been used thus far.
The change will mean both the Ford and Chevrolet V8s will have the same size throttle body, which has long been the preference from Supercars.
It is hoped that the smaller throttle body will improve drivability and rear tyre life, which have been issues for the Mustang compared to the Camaro so far this season.
Approval for the change follows the new throttle being tested by several teams since the Townsville 500.
"Supercars can confirm that the Ford homologation team requested an Engine Specification Document (ESD) change to use an 80mm throttle body," a Supercars spokesperson said.
"This has now been tested, verified, both on and off track, and is now approved for introduction for the Beaurepaires Sydney SuperNight.”
This is the second significant parity adjustment in as many rounds, with the Fords having debuted a new aero package in Townsville.
That too was centred on rear tyre life, with a re-positioned rear wing, gurney flap and boot spoiler hoped to improve rear stability under braking.
The jury was left out on how effective the changes were, however, despite a breakthrough win for Ford driver Anton De Pasquale on the Sunday.
Sydney should provide a sterner test for the new aero given its higher-speed nature compared to Townsville.