(Adds details from U.S.)

LONDON, Sept 27 (Reuters) - British engineering company Rolls-Royce said it had been selected to provide engines for the United States Air Force B-52 Stratofortress bombers, in a contract which could be worth up to $2.6 billion.

Rolls-Royce said its F-130 engines, which will be made at its Indianapolis, Indiana facility, were chosen for the replacement engines for the bombers, beating incumbent supplier Pratt & Whitney, part of U.S. company Raytheon.

"This is a major win for Rolls-Royce," Craig McVay, SVP Strategic Campaigns Rolls-Royce Defence, said in a statement on Monday.

The Pratt engines have powered the famous B-52 aircraft, which can carry nuclear weapons, since the 1960s but will be retired by 2030. The aircraft's manufacturer, Boeing, will integrate the new Rolls engines with the first due for testing by 2025.

Rolls-Royce said its F-130 engine will provide the U.S. with "vastly greater fuel efficiency" while the U.S. said in its statement that it would also increase range and cut maintenance costs.

The new engines will allow the bombers to continue missions into the 2050s. (Reporting by Sarah Young; Editing by Kate Holton and Alistair Smout)