To me, it depends on what you are going to do with it once it's finished.
Drive it - then convert to alternator, doing as Deano suggests
Show it - then keep it original
Sell it - then keep it original
The only other factor that comes to mind would be if the car has individual historical significance, in which case keep it as original as possible.
Last edited by Hamwich; 21/11/15 06:08 AM.