Anyone know if the A/C water pump is still available somewhere, and which pulley it's drilled for? The tech Wiki was unclear......

I'm not 100% sure, but I believe there is no special water pump for aircon. It is just the same as any other pump. However on a 1200, the fan shroud was used, and optional flex fan.

For B210 and B310, larger radiators were used with A/C. B310 also used a clutch fan.

a14 ac water pumps available here in aus from bursons still. they are slightly different.

What is different about them?

OK i've look into this more, for USA and Japan market:
* For Datsun 1200 (B110), there was only one water pump, even for air conditioning models
* For B210 and B310 there was a new Aircon pump starting 1977
* Other A14s used the same pump as 1973 A12 Datsun 1200

Aircon A14 From 0876
* 21010-H7225 (BA010-H7289) ASSY-PUMP WATER WITH GASKET From 0876 Optional FOR AIRCON A14 $57.17

This was fitted with a fluid-coupled large fan.

What is different about the water pump? Possibly only the bolt pattern on the pump pulley flange. It seems they moved to the 2.362" bolt pattern at this time.




Datsun1200 Tech: Water pump

Apart from the bolt spacing difference, the pulley mounting face offset differs aswell. If you run this waterpump you will also need the matching pulley so as to line up with the crank and alternator pulleys. If memory serves me correct, the impeller differs [fin shape and fin count] between these pumps also.

cheers
benny

There are pictures in the wiki showing the different fin and impeller shapes. However I suspect they are the difference between original cast Hitachi design and inexpensive aftermarket pressed steel impeller. Not meaning anything else ...?

The OEM items IMO are far superior and more effective at puping the coolant through the engine. The OEM cast impellers follow the contour of the water pump housing [part of the the alloy timimg cover]. Those pressed steel aftermarket impellers are just not up to scratch IMO.