The work, to be done in San Antonio, Texas, includes installing electronic and mechanical equipment, software upgrades and testing systems.
A Boeing spokesman said the change incorporation step is required for all new airplane programs. He said the company expects the plane to be certified this year.
Boeing said it will hire 450 temporary employees to join its staff of 1,700 workers based in San Antonio.
Boeing, the No. 2 commercial plane-maker after Airbus
Boeing has taken 843 orders for the Dreamliner, according to its website. That is a record number of orders for a Boeing plane still in development.
Shares of Boeing were down 2.5 percent at $70.03 on the New York Stock Exchange in early afternoon.
(Reporting by Kyle Peterson and Karen Jacobs, editing by Matthew Lewis)