Exactly right. 1981 would be a Datsun model series B310, which was badged as 210 (USA) or Sunny (Japan/ANZAC). Double-check by examining the engine compartment aluminum ID plate
Yes, it will bolt to the A12 engine. The most important swap consideration is the clutch release sleeve
That is 60A 5-speed gearbox, if i'm not mistaken. It's the only one with the boss jutting out of the left side
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