As the rumble of revs from 126 engines built to a thunderous peak, the line of tyre smoke from the world's largest simultaneous burnout erupted out from behind the trees in a long, continuous grey line, tainted curiously by small blobs of orange, green and even pink.

The smoke curled and built into a ball-sized plume high above the Summernats precinct, then broke into a pungent haze and began a leisurely drift towards Watson and Mt Majura.

In less than 30 seconds, it was all over.

And if the faint sounds of cheering from the Summernats crowd provided a measure of success, then the world burnout record was back in Australia's tyres once more.

Expectations had been building for weeks about the record attempt and the logistics required to make it happen delivered a mammoth task for event organisers.

The obscure automotive record had been held by Summernats for a number of years until, bizarrely, the Saudis lined up 119 cars during their national day activities in 2017 and pinched the title.

Since then, Summernats co-owner Andy Lopez had been plotting to win it back.

"We had set the record originally back at Summernats 26 and then again in Summernats 28 and then out of the blue, it was taken away by the Saudis," Andy Lopez said.

"We know that we need not just 120 cars, but more than than just to be sure and to make it stick," Andy Lopez said.

Preparations began early on Friday morning with a briefing for the safety teams, the fire crews and the marshals.

Over a period of 90 minutes, the participating cars were lined up in two long rows, separated by concrete barriers. The chances of one driver's foot slipping off a brake pedal or a major mechanical mishap occurring, were enormous.

But when the revs died, the smoke cleared and the numbers officially tallied by the official Guiness world record adjudicator, it was Australia's title once again.

Mr Lopez was delighted with the size of the crowds and the quality of the vehicle entries for this year's event.

"It's stinking hot, as we can always expect Summernats to be, and the place is heaving," he said.

A much-anticipated Friday highlight was a new feature called The Great Uncover, with the progressive revealing of 17 as-yet-unseen cars - including several from the local Canberra region - which had been kept under large black covers inside the judging pavilion.

"These 17 beautiful cars have been in the build process for between three to 10 years," Mr Lopez said.

"These are cars which are collectively worth between $10-12 million and represent years of blood, sweat and tears. So the guys and girls involved deserve as much fanfare as we can give them."

The Friday afternoon posting of the top 60 Elite category cars to make the final judging sparked a frenzy of interest. Ten Summernats judges, all experts in their field, meticulously assessed the entries using the key criteria of paintwork, interior, body, engine bay, and undercarriage.

"Overall, what we're always looking for is quality. Every car that wins in its category will deliver the highest quality," said Chief Judge Owen Webb.

The ACT Environmental Protection Agency said it had received just two complaints regarding the odour from the burnouts at Summernats, and no noise complaints.

No arrests or complaints had been made to police, and emergency services also reported an uneventful day at Summernats.