I would go to engine accessory contractors back before the SR71 tech was declassified, and I could always pick out the parts for that engine. For one thing, they wouldn't say what engine the parts went on. I was really surprised when I saw one of the engines sitting in the open at Pratt, it had just been declassified. I was sitting on my couch in Dayton when one flew over in the late '80s, the sonic boom was unmistakable. They set some records that day