It's time for the Great Race - Australia's annual touring car - or these days V8 Supercar - classic, the 1000km torture test at Bathurst, NSW.

Indeed, there are two great races this Sunday.

The other is the Japanese Grand Prix at Suzuka - a track in the side of a mountain almost as fabulous as Bathurst's Mt Panorama circuit.

As the Supercheap Auto 1000 concludes on the Seven Network late Sunday afternoon Mark Webber will set about defending, and trying to extend, his Formula One world championship lead against the four rivals snapping at his heels. That battle will be played out on OneHD and Ten.

Bathurst race day is one of those special days on the Australian sporting calendar.

The V8 Supercar drivers call it their "grand final", although - unlike football codes - it is mid-season.

Still, America's Daytona 500 is always at the start of the NASCAR year and the Indianapolis 500 open-wheeler "crown jewel in May, early in the IndyCar season.

There are some particularly special moments being celebrated at Bathurst this weekend.

It's 40 years since Allan Moffat's first victory there, in the brutal Ford Falcon GT-HO. Moffat's son James will be making his Bathurst 1000 debut in the Great Race, with Ford's factory team.

It's 30 years since a rock tumbled on to the track in the path of Dick Johnson's Tru-Blue XD Falcon. Johnson's misfortune that day was the foundation of his legend and he goes back this week with the V8 Supercar Championship leader James Courtney in one of his cars - and a big chance of winning the Great Race with co-driver Warren Luff.

There is, however, some fuss over the ownership of Johnson's team, with forklift tycoon Charlie Schwerkolt, who rescued it in early 2008, apparently having fallen out with Johnson, and 34-year-old mining magnate, champion racehorse - and now Newcastle Jets - owner Nathan Tinkler seemingly dipping into his reputed $600 million fortune to buy out Schwerkolt's half share.

And Holden Racing Team, which won at Bathurst a year ago, is turning back the clock by running a retro livery replicating that when it first won with Allan Grice and Englishman Win Percy in 1990.

This year's rules preclude HRT's regular drivers Garth Tander and Will Davison pairing again, so Cameron McConville - recently out of retirement - and David Reynolds will be their respective partners.

However, on form the black and white cars are unlikely to have anywhere near the speed and endurance that Eddie McGuire's black and white Collingwood "machine" displayed at the MCG last Saturday.

The Team Vodafone cars - Holden Commodores this year instead of the Ford Falcons with which it won Bathurst in 2006, '07 and '08 - are almost certain to be the ones to beat.

They would have finished one-two in the 500km warm-up at Victoria's Phillip Island last month except for a rare frontal problem on the Falcon of two-time V8 Supercar champion Jamie Whincup and Steve Owen.

In the other Vodafone car built by Triple Eight Race Engineering the driving duties will be shared by Craig Lowndes and Mark Skaife.

Lowndes is the modern-day Peter Brock, even having won the Australasian Safari in Western Australia since Phillip Island.

Skaife only races a couple of times a year now but has lost none of his ability and is far more relaxed than when saddled with the ownership burden of HRT at the end of his full-time career.

The other main contender must be the lead Ford Performance Racing Falcon of Mark Winterbottom and Luke Youlden.

Winterbottom has been at the pointy end of the V8 Supercar field for several years now and it surely is only a matter of time before he wins the big one - although don't raise that with Glenn Seton, back for his umpteenth try at Bathurst, this time sharing a Commodore with Jason Bargwanna, a former winner.

While little known to the wider public, like Whincup's co-driver Owen, Winterbottom's part-timer sidekick Youlden is making his 11th Bathurst 1000 start and has consistently finished well.

Seven is taking a production crew of 315 people to Mt Panorama, will have 168 cameras and 36km of cabling - that's six laps of the circuit.

What it will be hoping for is a turnaround in the sliding audience figures of recent years.

On the F1 front, with four races to go in the most fiercely contested world championship in history, the mind games are going up a notch.

Brit Lewis Hamilton, who has failed to finish three of the past four GPs in his McLaren-Mercedes but remains just 20 points behind Webber, is loudly questioning whether the Red Bull cars of Webber and young German Sebastian Vettel were legal mid-season.

"In Hungary they were two seconds a lap faster than the rest of us - it's simply impossible to have a lead like that," Hamilton said.

The Renault-powered Red Bull RB6s have come back to the field recently, which Hamilton and McLaren attribute to stiffer tests of the front wings which rivals claim had been flexing to advantage at high speeds.

Red Bull team principal Christian Horner has said: "A lot of fuss has been made about the front wing. Before that it was the diffuser, the week before it was the suspension, the week before that it was active ride height.

"At the end of the day we are very happy that the car complies with the regulations and the tests that the FIA (governing Federation Internationale de l'Automobile) have carried out.

"The car is in compliance with the regulations."

The main challenger to Webber is Ferrari's Spanish dual world champion (albeit with Renault rather the Italian team), Fernando Alonso, winner of three of the past five races, including the two most recent in Italy and Singapore.

Only 11 points separate Webber and Alonso, although there are only 25 points between the top five - with Hamilton, Vettel and McLaren's Jenson Button, world champion last year with the Brawn team that is now Mercedes' factory entry, also still in the hunt.

"It's nice that I have a little buffer," Webber said.

"I'm glad of that - but we have still got to go out and give it all we've got (in the remaining races).

"The momentum is with Ferrari, as they have had two victories on the bounce - and don't forget McLaren.

"At Suzuka we have to get the absolute maximum out of what we have.

"But Suzuka is a track that, like all the drivers, I really love."

For drivers and fans alike, this is a weekend to love.