The number on the Shermans and other tanks was 95,000, of which we gave 11,000 to Russia. I've heard the Iran story, but haven't confirmed it in any sources yet. But it's a big difference for Stalin to go to war over Iran, which he almost certainly couldn't hold and never occupied the way he had eastern Europe, and Germany or Poland. But the point is BOTH knew they couldn't win based on their strengths---his conventional forces couldn't be stopped without our atomic bombs, but we couldn't invade WITH the atomic bombs. Stalemate.
Cheers!