Ben Rich's autobiography (Skunk Works) talks about how they weren't allowed in the competition because they had already developed the SR-71 and Have Blue (the prototype for the F-117), this is talking about the project to build what would become the B-2 and the DoD wanted to see if this was a fluke design or if it could be repeated. Lockheed kept their research secret, but the CIA gave Northrop, McDonnel Douglas, Rockwell, Boeing and Grumman the stealth data they had gotten from a few spies (mostly one, though, and his story is covered in Hoffman's "The Billion Dollar Spy") and they came up with a lot of nothing. So Lockheed showed up with the F-117 and another, unspecified design (which a lot of people think is the Aurora, but the less said the better) and it was leaps and bounds ahead of every single design submitted (but Rockwell, Gruman and McD/D literally only submitted drawings because they didn't think anything could meet the Pentagon request) . They eventually had 3 designers stolen by Northrop who worked on Have Blue and then Northrop resubmitted their flying wing design with the improvements and the B-2 was born