im installing a water pump in my 97 z28.. i there is a "coupling" that goes between the pump and the engine and that coupling has a groove on one side.. does it matter which way the coupling goes on?
and i was looking at a diagram in my haynes manual and it shows 2 O rings on this assembly, i only see one and its on the new water pump.. am i missing one?

 

Groove on the coupler goes toward the engine. There is a o-ring on the drive stub from the front of the engine and a o-ring on the pump shaft.

 

thanks