I need a new alternator for my 2005 V6 Mustang. When looking on Ebay to buy one I noticed some are 110 amp and some are 135 amp which one should I buy for my Mustang ? Both claim to be for a 2005 V6 Mustang

 

Either will work. However, if the existing unit is of less than 135 amp capacity, the overcurrent protection devices, namely fuse links, may be of inadequate size for the 135. No big thing, as taxing an alternator to it's limit is not the usual event; adding energy-hungry devices can do that, big amplifiers, etc.