Any Auto parts store that sell Delco parts, you will be using your old pulley & brackets.

 

i had the exact same problem.. i made a post an everyone commented on it... i got all sorts of ideas. funny thing was is it turn out to be a amparge draw from the fan motor. so check the car with the key foward an the engine off for the amprage. then with the car running do the same. the amprage draw should go up but if it jump for high hevan then you no you have a problem.

 

The zz4 will not have more power requirments than any other motor. Weither it be a 305 or 350 or zz4 350. Accesories have the power needs. If you have A/C it should definatly have a 105 amp.
What is the condition of your battery?