Here's my cheap one wire alternator.  Ok, don't blow a gasket...yes it's a GM alternator.  But I'm cheap and this was the cheapest way I could find for a one wire upgrade.  This is part no 778-66904 from Jegs for a cost of $69.99.  It's a 70 amp.  They also have chrome 80 & 100 amp models for more dough.

Notice the small bracket that had to be made to allow this alternator to bolt up.  The spacing of this GM alternator was about 1/4" off from hole to hole.  But the 1/4" X 1" X 2" bracket saved the day.

The fan blades are from the GM alternator and the pulley is my original underdrive unit.