If Mercedes-Benz isn’t the much-vaunted fourth manufacturer set to join V8 Supercars next year, then much of the pit lane has got it wrong.

After several weeks of speculation, there is widespread acceptance among V8 teams that cars bearing the famous three-pointed star will race in the first event under the new Car Of The Future rules next March.

The V8 fraternity has been abuzz at Sandown this weekend with an expected announcement that long-time Ford-backed team Stone Brothers Racing is just days away from switching to Mercedes-Benz.

Well-informed scuttlebutt has SBR, which is known to be losing its multimillion-dollar Ford backing at the end of this year, forming an alliance with Melbourne-based sports car team Erebus Racing, which is believed to be funding the effort.

While the entry of at least three Mercedes-Benz E-Class V8 racers by SBR from next year is regarded as a done deal, there is still much debate about factory involvement.

Rather than a Mercedes-backed campaign like Nissan’s official entry in partnership with Kelly Racing next season, it is understood that Erebus Racing has contracted the German car-maker’s AMG performance division to engineer and build V8 Supercar-specification cars.

Although sanctioned by the company’s head office in Stuttgart, the Erebus/SBR plan – developed in secret over several months – was rejected last month by Mercedes-Benz Australia, which announced that V8 racing didn’t fit the prestige brand’s image in the local market.

But rumours persisted that the project, believed to be costing $20 million over three years, had gone too far to be abandoned and, sure enough, earlier this week the V8 bush telegraph was reporting that it was alive and well – and soon to be officially announced.

It appears the support of senior AMG and Mercedes executives, including Mercedes-Benz Motorsport boss Norbert Haug, has convinced the company’s local management to tolerate the plan without providing any direct funding or sponsorship.

There is enough knowledge of the scheme doing the rounds of the V8 paddock to indicate that, in one form or another, Ford, Holden and Nissan will be joined on the grid next year by Mercedes-bodied cars.

According to several sources, the SBR/Erebus/AMG alliance will be officially announced before the Bathurst 1000 early next month – and most likely within the next week.

Erebus Racing, which is owned by wealthy Sydney-based property developer Betty Saunders-Klimenko, has close links with AMG through its success in local GT racing with the racing version of the Mercedes-Benz SLS sports car.

Certainly, while not mentioning Mercedes-Benz, V8 Supercars is doing nothing to discourage speculation that the Car Of The Future initiative, which opens the sport to any car manufacturer after being restricted to just Ford and Holden for nearly 20 years, is poised to attract another newcomer in addition to Nissan.

”There will be four manufacturers on the grid at the start of the next championship year,” V8 supremo Tony Cochrane told The Sunday Age at Sandown Raceway yesterday.

”I was certain of that at the Nissan announcement back in February and I’m absolutely certain of it now. There will be four different makes of cars in V8 Supercars next year.”

In a curious twist, amid the rampant speculation that SBR’s impending defection from Ford to Mercedes-Benz would soon be revealed, the team scored its first wins of the season at Sandown yesterday.

SBR spearhead Shane van Gisbergen secured pole position for this afternoon’s Dick Smith Sandown 500 by running away with yesterday’s second qualifying race.