I use a Denso 60 amp alternator on the 512 EFI engine in my Duster. That engine has coil packs as well as EFI. The car has a big electric fuel pump as well as an electric fan for the trans cooler. It stays right at 14.5 volts at idle and while driving. Zero problems keeping up with the EFI system. I am going to put a 90 amp Denso in my Coronet but it doesn't really need it. I'm just putting it on the engine since I have it and I think it looks cool.