It's understood that Ford declined to sign off on the VCAT aero homologation test that took place with the Mustang and Camaro prototypes in Queensland recently.
That was despite Supercars leaving the test satisfied with the aero parity between the two cars.
In meetings since then Ford has requested additional data for its own analysis.
While sources have indicated that Ford's concerns are primarily based on that VCAT data, Supercars technical boss Adrian Burgess says the ongoing discussions with Blue Oval officials involve a holistic – and evolving – approach to finding parity.
"The process isn’t finished," said Burgess. "The process is quite complex and long.
"Our parity process is over many pillars of parity, so until all of the homologation process is finished, we will continue working with both of the manufacturers and obviously Supercars and the homologation team until we’re all happy and that the process is actually finished.
"We’re working with them. We speak with them daily. The homologation of the car is over many factors and that isn’t finished yet, so the car isn’t homologated.
"We’re ticking off a couple of pillars of parity but it’s an overall that gives
us the car, gives us the close racing and they’re all interlinked.
"So whilst aero is one part of it there are other parts that feed into that same parity and we continue to work with them and work on the two cars to achieve that."
While it's understood Supercars can sign off on the aero homologation without Ford's approval, Burgess emphasised the importance of having both manufacturers comfortable with the outcome.
"Of course we care what [Ford] thinks and we talk with them daily. But it’s a
process," Burgess explained.
"The other parts of the parity process need to come together to actually make sense and then for both manufacturers and Supercars to agree that the cars are homologated.
"There’s no interest in Supercars signing off on something when we haven’t got everyone else lined up with it. They’re all interlinked.
"Unfortunately the media hype is focusing on one part of the process, but I need a couple of other parts of the process finished and aligned so that they make sense together."
Burgess added that he is comfortable with the VCAT and general homologation processes despite Ford's concerns.
"We're very confident in the process and we're very confident in the numbers. But this is a bit of a journey that everybody is on," said Burgess.
"There are other factors that we've been working through in our circuit testing that we're still finalising, hand in hand with both of our manufacturers, that will bring more confidence to the overall picture.
"Unfortunately at the moment we're all trying to look at the overall picture, but we're still making it. That's not saying we're not organised. That's to saying we've run out of time. We haven't.
"For example engines; HPE has got six [Ford] production engines finished. But they haven't been delivered to me yet, so I haven't run through them all on the dyno to make sure they are all the same.
"So in terms of setting that final, small number, in terms of engines, I need to run production engines. With one or two development engines I can get a capture of what they are, but I need the production parts.
"With that confidence, and that being finalised, that will then bring the rest of the pieces of the jigsaw together.
"That's what Ford is talking to us about, and we are talking very openly and confidentially with them. We don't need to publicise it up and down the paddock.
"Everyone is comfortable with the process and we're working hand-in-hand to make sure we all come out of this with a car that we're all happy to homologate."
