The tentative contract that General Motors has worked out with the United Automobile Workers union is going to raise the automaker’s cost of labor and require a significant cash outlay.

But G.M. won something that it had rarely attained in the past outside of bankruptcy: the ability to close three plants economically.

Now the union is likely to try to win similar monetary gains from Ford Motor and Fiat Chrysler. And those companies may find them more costly, on a relative basis, said Kristin Dziczek, vice president for industry, labor and economics at the Center for Automotive Research in Ann Arbor, Mich.

“Ford and F.C.A. don’t have three plants they want to close,” she said. “So what will they win?”

G.M. workers will vote on the contract this week, with a result expected on Friday. Most union locals will hold seminars to outline the contract’s details to members, and they allow voting over two or three days.