The Scottish Roads Partnership (SRP) will start work later this year, with completion due in the spring of 2017.
The upgrade work will see the six-mile "missing link" completed on the M8 in North Lanarkshire.
Improvements to the Raith Interchange and widening of key sections of the M8, M73 and M74 are also part of the plan.
The work will see upgrading of the A8 between Baillieston and Newhouse to motorway standard.
This will require upgrades to the connections to the M73 motorway at Baillieston and a new junction at Shawhead, which will connect to the A725 East Kilbride road.
There will also be new junctions at Eurocentral and Chapelhall.
Improvements to the Raith Interchange near Hamilton in Lanarkshire include realignment of the A725.
There will be an underpass for the A725 and bridges carrying the Raith roundabout.
SRP is a consortium of Ferrovial Agroman, Lagan, Amey, Cintra, Meridiam and Uberior.
Scottish Transport Minister Keith Brown said: "This project will boost the nation's economy by improving connections for business across Scotland and will directly support the hard-pressed construction industry.
"The M74 Completion generated 900 construction jobs and we expect this project to be on a similar scale. There will also be opportunities for on the job training for apprentices and local employment.
"These improvements will also greatly improve road safety and accessibility by playing an essential role in reducing frustration and accidents and providing easier access to and from a number of communities and locations, such as Strathclyde Park."
The improvement are expected to cut up to 18 minutes off the journey time for the busiest sections of the M8.
SRP will now speak to sub-contractors to determine whether it will be able to deliver the project for the estimated cost of £415m.
The preferred bidder has been announced for a £415m project to upgrade the motorway network in central Scotland.