Tach gage, Generator to Alternator

[Dave_Vrba@mail.sel.sony.com (Dave Vrba)]

     Ok listers, another question arises when we are talking about 
     replacing our mechanical tach drive generators with alternators.  What 
     does one do to replace the mechanical drive tach gage itself to 
     maintain the originality "look" of your dash?  With no more mechanical 
     drive to the tach, the original is useless.  Right?  What do we use to 
     still have a tach (electronic I assume) and have the "look" like it 
     should be there?
     
     Curious,
     
     Dave Vrba
     '62 MKII Sprite
     Dublin, CA