Supercars signed off on the changes following high-speed testing during dedicated running with a Tickford Racing Mustang at the recent Bathurst 12 Hour.

The updates consist of an additional set of pins that ensure the boot lids remain sealed under high loads, and stiffer composite doors.

Dick Johnson Racing and Tickford Racing worked on the changes following analysis of the lack of top-end performance noticed by Mustang runners at last year’s Bathurst 1000.

Negative impacts of panel deflection – including the boot lid coming slightly open down the straights – was identified as a potential reason for the deficit to the Chevorlet Camaros.

Supercars motorsport boss Tim Edwards affirmed the category led the move to stamp out deflection it had observed.

“That was an instruction from us. We weren’t comfortable with the way they were moving around,” Edwards told Speedcafe of the panel changes.

“If you look on the back of the Ford now, you’ll see it’s got fixings in the rear boot face to try and hold that rear boot face in the position it was when it was in the wind tunnel.

“They were poorly fitting, some of them, and moving around, and there were some other areas around the door we weren’t happy with as well.

“They were instructed by us that they needed to stiffen those areas up, and what they’ve done with the boot is put extra fixings in to hold it in position.”

Asked if Supercars issued the instruction because it knew for sure the deflection was causing issues, or if it was a case of closing off a potential problem, Edwards added: “A bit of both.

“We’ve done CFD studies on a lot of these things in the correct positions or potentially a position it could move to because of flex. So, we know the results of that.

“But fundamentally, the way the cars were homologated, they weren’t moving…

“So, prior to any of that [CFD testing], we already headed down the path of, that’s not how they ran in the wind tunnel, so it needs to be addressed.

“We do know the differences from the CFD studies as well.”

Ford introduced lighter body panels over multiple stages towards the end of 2023 and start of ’24 in a bid to reduce panel weights.

The shape of the bodywork currently being run on the Mustang and the Camaro was signed off following testing in the Windshear wind tunnel in the United States ahead of the 2024 season.