64-66 ammeters are a shunt type already, Bill, and not fused at all. I am using mine still, I did add 1 amp fuses on each lead like the 67-72's used. Seems like the burnt ones didn't work IIRC(been a long time since I restored mine). Mine has been doing fine, even using a later higher amp alternator. Shows discharge when lights on/engine off and shows charge when running, but the needle moves a little more than before the alternator upgrade.
