The South Australian Government has released the final design of the state's biggest infrastructure project for community feedback.
The plans show the northern section of the Torrens to Darlington road project, from the River Torrens to Anzac Highway, for the first time.
Premier Steven Marshall said it was "the toughest component of this overall project".
"It was left to last but it didn't bother us because we're now getting on with delivering a fantastic completion to the north-south corridor project," he said.
The plans include an elevated roadway north from Ashwin Parade to protect the Brickworks heritage site and a tunnel entrance at the current Torrensville Bowling Club.
The eight-year-old Thebarton Community Centre will be demolished to build the entrance to a new tunnel, but the government said much of the area's heritage would be preserved.
"We get to keep the Thebarton Theatre, the Hindmarsh cemetery, the Brickworks and the Queen of Angels church," Mr Marshall said.
The Warriappendi School at Marleston would be among the properties to be acquired to make way for the final section of the upgrade.
Transport Minister Corey Wingard said the government was working to relocate the school before the end of 2024.
The government said the project would create 4,900 jobs during the peak of construction, which would begin in 2023 and end in 2030.
It said 393 properties would be acquired for the hybrid tunnel and lowered motorway plan — fewer than other proposals for South Road — and that residents were notified as the design for each section was finalised.
"So we did do it stage-by-stage to make sure we were letting people know as soon as possible when we had certainty about what was happening with their properties," Mr Wingard said.
But some residents, businesses and community groups said it had been hard to get information about the project and the new plans had left them disappointed.
Torrensville's Bowling Club, which opened just two years ago, was initially told they would only lose part of their greens and clubhouse.
But the new design will force the club to relocate.
"We've had to really dig in and ask questions but they would turn around say, 'oh, we'll let you know eventually'," club president Dean James said.
"We didn't have the answers … and as far the government, well, unfortunately, I think they've let us down."
The opposition accused the government of being secretive about its plans to acquire properties.
"This is a good project but the government are stuffing it up," Shadow Transport Minister and West Torrens MLA Tom Koutsantonis said.
Construction will start on the northern section of the road in 2026, with the southern section beginning in 2023.
The 78-kilometre North-South Corridor, which will create a direct route from Gawler to Old Noarlunga, is expected to be completed in 2030.
