Very often the industrial engines have certain heavy duty components to help ensure reliability in the hands of uncaring operators, or when the engine is operated at full rated output for long periods, like in generators or pumps.

I have no idea what an A15 would need by way of beefier parts, but an exhaust manifold & induction change, along with a suitable cam change, & this engine will give your Datsun some 'Industrial Strength' grunt.