In this image what would be different if it were a Delta to Delta Trafo?????

[GoldDigger]

So the Wye primary with no accessible wye point does exist! I am assuming from the phasor diagram that the wye point is not brought out. Would such a unit just be used equivalently to a delta primary?

At a minimum the phase relationship between input and output will be different!

 

[mbrooke]

At a minimum the phase relationship between input and output will be different!

By a 30* phase shift, and, secondary voltage division under an open phase would be different. However, when all is said and done under normal service the transformer will behave and function equivalent to a delta primary.