There is an intriguing contrast in recent Australian and US reports on the development of a possible future top-line Cadillac.

General Motors Australian unit Holden’s head of engineering has “flatly rejected” reports that the company is developing a V12 engine and platform for a new flagship Cadillac model that would rival the Mercedes-Benz S-class, according to a local report.

“It’s definitely not happening,” Holden’s executive director of engineering Tony Hyde told Australian online motor industry publication GoAuto news.

The Australian report noted the automotive world had been set buzzing following US reports that quoted General Motors vice-chairman Bob Lutz as saying, on a recent visit to the UK, that development work was “well under way” in Australia for the car, which would be based on the Sixteen concept shown at the 2003 Detroit motor show.

GoAuto news said Lutz, who heads GM’s global product development, was reported to have said, at a Hummer dealership opening here in Britain a couple of weeks ago, that Australian engineers were already working on the new V12 engine.

Holden is now ‘rear drive platform central’ for GM as it moves to greater global use of its vehicle architectures and model names. The company has decades of experience designing, engineering and building large, rear-drive six and eight-cylinder sedans, wagons and pickups primarily for the harsh Australian environment. Over the last decade, Chevrolet-badged Holden Commodores have displaced US models in the Middle East and the unit also adapted its Monaro coupe (left-hand drive, mild restyle, relocated fuel tank, etc) to become the US-market Pontiac GTO.

The Australian report said that US publication AutoWeek had claimed the 7.2-litre V12 engine is basically two 3.6-litre Commodore V6s joined together on a common crankshaft, and develops around 390kW.

Holden’s separate engines operation in Australia builds versions of GM’s relatively new ‘global’ V6 for use in the locally designed and made Commodore model line and also exports some motors to other GM units worldwide.

GoAuto news cited US reports claiming the V12 is already being tested at Holden’s Lang Lang test track in Victoria state but noted Hyde had said that Holden was not working on anything remotely like a V12 Cadillac.

“We are definitely not doing it,” Hyde told GoAuto news. “It might be possible to join two V6s, but we are not doing it. None exist in our part of the world and we are certainly not testing anything like that at Lang Lang.”

The report added that the ‘Cadillac Twelve’ or ‘XLS’ would reportedly be built on Holden’s ‘Zeta’ rear-wheel drive platform, which also underpins the VE Commodore and other cars including the forthcoming Pontiac G8 derivative [and a similar Vauxhall model confirmed for the UK] and Chevrolet Camaro.

GoAuto news said Hyde’s comments cast doubt on the credibility of the reports and the entire project – unless it is being done elsewhere.

“We are not working on any Cadillacs,” Hyde told the publication, adding: “Nothing. We’re full-up in terms of resources with Camaro and our own cars. (And) the G8 is a challenge from a timing point of view.”

Just-auto contributor Julian Rendell, who helped with AutoWeek’s report, said on Wednesday that Lutz had told UK car magazine Autocar at the Geneva show early this month that he’s planning some new, as-yet-unseen, super-luxury Cadillac.

“I interviewed Lutz in Manchester [during the Hummer dealer opening] and he definitely confirmed the engine project was going on and put it in the context of a car ‘something like the Cadillac 16’,” Rendell told just-auto.

“Lutz confirmed it was a Tom Stephens project [he’s the group vice president responsible for GM Powertrain] and was based on two hi-feature V6s joined together. He said Holden had some spare engine development capacity.

“I quizzed him on the capacity… and he confirmed the 3.6. The power? Double what the 3.6 makes.”

Rendell said Lutz’s point was that it’s an engineering programme exploring a future, big capacity, multi-cylinder engine. “We might need a big engine and we’ve got to find out if and how we can do it,” Lutz told the journalist.

“I didn’t have time to talk about the car, but… I’d be very surprised if there’s not a lot to this,” Rendell concluded.

Graeme Roberts