It's a mechanical distributor mod, the mechanical dizzy comes with mechanical timing, and vacuum advance, which I'm going to make use of. If I were to use this to forcibly convert an EFI engine with no way to hack a mechanical dizzy onto it, then i would need to worry about timing advance, but that's a different project for a different day.The issue with driving the transistor directly by the hall sensor is that although you can set timing based on sensor placement, there will be no advance curve. Not sure what this is for but it will limit the powerband. Have you thought about the advance curve?