Slade’s car had been engineered by the team’s high-profile competition director Ludo Lacroix since Mirko De Rosa’s departure in April.
Gilliam was recruited by the team in the wake of that post-Taupo move and has been data engineering across both the Slade and James Golding-driven cars.
The youngster will be known to some Supercars fans as a sim racing ace, previously driving for Tickford Racing and Matt Stone Racing in the category’s eSeries.
PremiAir boss Peter Xiberras says the squad is keen to test Gilliam’s engineering mettle in a leading role.
“Basically we’re just trying to give young Andrew an opportunity,” Xiberras told Speedcafe.
“He’s come onboard as a data engineer but Ludo can see something in him.
“With Ludo’s guidance over the top, we’ll just see how he goes this weekend as a race engineer.
“He’s a very intelligent young man, there’s a lot of knowledge in that young mind.”
Lacroix joined PremiAir over the summer following decorated stints at Triple Eight and DJR Team Penske.
Asked if it was preferred to have Lacroix higher up in the engineering structure than a race engineer role, Xiberras added: “Ultimately yes.
“That’s why we employed him to begin with, but sometimes you’ve got to move people around to see where they best fit into the puzzle.”
While there is plenty of intrigue as to who will drive PremiAir’s #23 Camaro next season, Xiberras downplayed the notion that the team is already preparing for 2025.
“We’re not looking that far ahead at this point in time, we’re just concentrating on this weekend,” he said.
Slade ended Friday practice at Symmons Plains in 12th, 10 places behind the sister Nulon Racing Camaro of Golding.