Experimentation with the Ford Mustang’s engine maps and shift cut will continue through both practice sessions at Symmons Plains tomorrow morning.

It is understood that as many as four different combinations of engine calibration (map) and shift cut time will be employed across the two, 30-minute sessions.

A map is believed to have already been locked in for the competitive sessions of the weekend – qualifying and racing – but the shift cut time is yet to be determined.

In Practice 1, five cars will run on a new calibration for Symmons Plains, three will run on the calibration which was used at Wanneroo last time out for comparative purposes, and another three will run on a different calibration again, as a trial for future events this season.

All cars will complete that session with the standard 50ms shift cut.

In Practice 2, all cars will run on the Symmons Plains calibration, but some will have a 30ms shift cut and others the 50ms cut.

Supercars will then make a decision about which cut setting will be used for the engine map which has been locked in for this weekend.

It comes after what is understood to have been an extensive, collaborative effort between Supercars and Ford homologation team Dick Johnson Racing in a bid to overcome the issues and achieve parity.

Tickford Racing’s Tim Edwards said during today’s team principals press conference, “There’s some refinement going on this weekend, and there’s some testing that’s going on in the practice sessions, much like the testing that happened in Perth [where] some of Fords ran a different shift cut to others.

“I believe they’re doing a similar thing on the GMs [Chevrolet Camaro] as well tomorrow, so they’ll use Practice 1 to evaluate some differences between them, and then they’ll make a decision before we go into qualifying.”

Changes are also likely to come for the Camaros, with both models of car having been run on a chassis dyno in recent days/weeks.

Barry Ryan, whose championship-leading Erebus Motorsport team fields Camaros, said earlier today, “Obviously, we just hear what we hear, and there’s nothing really official yet, because we’ve got to set all the ESDs [Engine Specification Documents].

“So, until the ESD’s set, we can’t really say it’s a parity adjustment, so we’re still trying to fine-tune the engines.”