USSR exported their SAMs to China starting in 1950s. They had a mutual defense treaty before the split. The treaty did not end the moment fissures started to ap

USSR exported their SAMs to China starting in 1950s. They had a mutual defense treaty before the split. The treaty did not end the moment fissures started to appear. I can't find any report on the defense tech exports to China well after the split. If you have references please share. Keep in mind that even now Russia sells rocket engines to the US.