All 10 Mustangs are present at the circuit fitted with freshly rebuilt engines, but not the ones featuring the recently homologated GT3 crankshaft.

Engine supplier Motorsport Powertrains and Ford Performance have been in a race against time to supply motors with the new cranks following a series of failures at Sandown.

Teams were informed last week that the new engines are scheduled to reach Mount Panorama on Friday, although there is optimism that an earlier arrival could be on the cards.

A global effort has seen crankshafts sourced from the United States and United Kingdom via Japan, with the makeshift supply chain including a Time Attack ace and mystery man ‘Peter’.

The GT3 crankshafts are essentially the same specification as the previous units, albeit said to be of a higher quality.

Supercars’ motorsport manager Tim Edwards told Speedcafe that ensuring the Moment of Inertia of the Ford engine remains the same as the Chevrolet was the category’s only concern.

“The only thing we needed to homologate on the crank was the Moment of Inertia,” Edwards told Speedcafe.

“Because it’s got different balancers and things that go with it, the only thing we have any interest in is, does it have the same MOI?

“Obviously, you don’t generate more horsepower or anything like that with a crank because it’s not that kind of tool.

“You just want to make sure it has the same rotating mass, so that’s got the tick-off from us.”

Edwards affirmed that the upgrade includes a larger harmonic balancer, which helps even out any MOI change from the crankshaft.

“Hopefully it will help the crank as well,” he said. “Obviously, balancers have an important function because it’s all got to be a matched package to make sure it’s doing its job.”

Supercars says it’ll be up to teams when they fit their upgraded engines once they arrive.

All Supercars engines must be tested on Supercars’ category dyno, operated by Craig Hasted in Brisbane, and sealed before they are handed over to teams.

“We’ve always got to be advised when anyone is doing an engine change,” explained Edwards.

“But we’re totally across it because of the vast number of engines that have had to come through Craig’s dyno in the last couple of weeks.

“All teams will have different approaches to it. Some might want to fit it [as soon as they can], some might say they want to save theirs and fit them Saturday night.

“That’s always been a team thing. But from a Supercars point of view, whenever they want to fit their race engine, it’s granted that it’ll be approved.”

It’s expected that all teams will opt to run their upgraded motor in the race, although the Blanchard Racing Team has expressed a temptation to stick with its higher mileage, known-quantity cranks.

Edwards flagged earlier today that Supercars will enact minor engine parity changes ahead of the Bathurst 1000, following much-publicised transient dyno testing in the United States.