The Datsun A12 engine is the most common A series engine to be found. They are commonly found in most countries and came out in the B110 and B210, known as the Datsun 1200 and 120y.
All A series engine blocks, from the 7/73, were modified with a better method of providing oil to the camshaft, the distributer moved back and the altenator swapped from right to left.
specs are:
Bore: 73mm
Stroke: 70mm
Conrod: 121.5mm
Block Hieght: 189.1mm
Displacement: 1172cc
Power: 69hp