Water pump return/inlet tube

[Dr.Jeff]

Just curious. I saw a listing on MWB for a water pipe gasket, to the water pump housing's inlet, that states it's for "AC" pumps and it has 3 bolt holes:
https://www.midwest-bayless.com/FIA...inlet-gasket-wac-fiat-x19-1975-78-oe-nos.aspx

Not to be confused with the thermostat housing gasket with 3 holes:
https://www.midwest-bayless.com/Fia...ng-elbow-gasket-fiat-bertone-x19-all-new.aspx

My AC water pump has the same tube as non-AC pumps, with 2 bolt holes:
https://www.midwest-bayless.com/Fia...rn-tube-gasket-fiat-x19-128-yugo-all-new.aspx

I did not know there was a 3-bolt version of the water return pipe? Is that only for the earlier models with the long shaft that extends across the back of the block? :
https://www.midwest-bayless.com/FIA...-pump-assembly-wac-fiat-x19-1975-78-core.aspx

I'm not very familiar with that particular early AC water pump arrangement. So just wondering.

 

[kmead]

The early AC ran the compressor off the back end of the engine using the drive extension off the back of the water pump. This was an all around peculiar approach to solving the problem.

 

[Dr.Jeff]

Is that what the 3-hole water pipe gasket is for?