Ford and Holden teams have reacted swiftly to meet Supercars’ centre of gravity measures, to be introduced this weekend at the Tyrepower Tasmania SuperSprint.

All Mustangs and Commodores will compete with redistributed weight in a move designed to raise their centre of gravity to match that of the Nissan Altimas.

Supercars undertook COG tests on 10 cars after the Beaurepaires Melbourne 400, before relocating ballast weight to equalise the field.

Although the weights have not been publicly released, Supercars.com understands the Ford teams must reposition more ballast than their Commodore counterparts.

The changes do not affect the overall 1,395kg minimum weight for each car, with the ballast simply being moved from its current position on the floor.

Holden’s ZB Commodore and Ford’s Mustang debuted in 2018 and ’19 respectively needing considerable ballast to meet the minimum car weight, due to extensive use of composites.

Teams ordinarily choose to place their ballast as low as possible to lower the car’s centre of gravity, which improves handling.

The same changes are now being made to every Mustang and to every Commodore, based on the average of the cars tested from each marque.

The homologating teams – DJR Team Penske and the Red Bull Holden Racing Team – nominated where the additional ballast was to be placed in their cars, which was then approved by Supercars.

Tickford Racing boss Tim Edwards says finding a way of affixing the ballast in the roof was no easy task for the Mustang runners.

Lead ballast clamped on the main hoop of a Tickford Mustang

“Initially they (DJRTP) just talked about putting it [the ballast] in the roof skin, but there’s too much weight being added to do that safely,” Edwards explained to Supercars.com.

“The only way we were comfortable with that amount of lead was to wrap it around the roll cage and then hold it on with clamps.

“Half of it is on the main hoop, then there’s the two diagonals that run on the left-hand side of the car that have another six on one and eight on the other.

“It’s effectively four wraps and none of them are over 10kgs, which makes it a bit easier to do.”

The process has been a little simpler for Holden teams, with lead ballast blocks bolted to the top of the roof’s leading edge, such as the Brad Jones Racing example pictured main and below.

"There's one standard Commodore part left in the roof, the front of the roof, and that was the spot they chose to put the ballast," Erebus CEO Barry Ryan told Supercars.com.

"There's a drawing that comes from the homologation team and they tell you what the size lead blocks need to be and where they need to be put.

"You make the lead blocks and bolt them in, it was as simple as that. It's probably a day of work for two people to do it all.

"We managed it pretty quickly, as soon as we saw it. We made sure it didn't affect the key mechanics' preparation on the cars.

"We just made it happen pretty smoothly and by the end of the day it was done. Really the mechanics didn't even notice.

"You had to take the roof off but it's not that big a problem."

The exact performance impact of the changes is currently unknown, with teams tipping it to vary depending on the circuit.