Time for Russian gear. The MiG-25 was designed to intercept the B-70 but B-70 was not build. But there were a lot of other appropriate targets for the MiG-25, like the B-58. After the flight of Belenko to Japan and the investigation of the aircraft trough American specialists the avionics was totally altered to prevent American measures. So a new version of the MiG-25 with totally new avionics was build and the investigation of the technique of Belenkos MiG-25 was useless for NATO. The advantage of the Soviet was that no Russian high tech weapons ever came near American investigators to develop appropriate countermeasures before the end of the Soviet Union. I like cold war stories, because today we can now read the stories from both side view.