New Walkinshaw Andretti United signing Chaz Mostert is set to continue his alliance with top engineer Adam De Borre next year.

Today it was finally confirmed that Mostert will leave Tickford Racing and join WAU in what is the biggest switch in the silly season.

Speedcafe.com understands De Borre, who has engineered Mostert for all bar one season of his Supercars career, is poised to follow the 2014 Supercheap Auto Bathurst 1000 winner to the Clayton squad.

The pair have struck up a strong relationship over the years which was only broken when De Borre joined DJR Team Penske for a single season in 2016, before returning to partner Mostert at Tickford the following year.

De Borre has engineered Mostert for each of his 13 Supercars race wins with the last victory arriving at Melbourne’s Albert Park in March.

WAU is, however, yet to confirm the engineering roster for its new look line-up that is likely to see Mostert joined by Super2 Series winner Bryce Fullwood.

Mostert’s team-mate at Tickford Racing this year, Lee Holdsworth, believes securing De Borre’s services at WAU would have been a key part of his multi-year deal negotiations.

“I think for him, that’s the important one. I think for him to take Adam with him is where… that was the selling point,” said Holdsworth on Fox Sports’ Loud Pedal podcast.

“To be able to go – if he had a few options – it would have been ‘Who can take Adam and not have him full time?’ because he’s not full time at the workshop.

“He works from home and comes into the workshop when he needs to, does his work in there, prepares the car, gives the boys all the numbers and everything, and is at the race meeting, and does a fantastic job.

“If you’ve got a good engineer, you can turn a car around. Everyone’s got much the same resources so… time will tell but, I think if you’ve got the right engineer, you can do the job in pretty much any team.”

Mostert will head to WAU having finished fifth in this year’s Supercars Championship.